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Pseudomorphs & Replacements A & B
Posted by Rock Currier
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Pseudomorphs & Replacements A & B November 21, 2010 10:09AM |
Click here to view Pseudomorphs & Replacements C. Click here to view Pseudomorphs & Replacements D to I. Click Here to view Pseudomorphs & Replacements J to M. Click here to view Pseudomorphs & Replacements N to P. Click here to view Pseudomorphs & Replacements Quartz. Click here to view Pseudomorphs & Replacements R to Z. Click here to view Best Minerals P, click here to view and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?
I don't think I have ever seen so many minerals in one place with captions containing so many question marks, Possibles, Presumablies, Probables, Seems to bees, Unknowns, Could bees, Maybes and Yet to be determineds. And of those images that don't have one of the forgoing qualifiers, certainly more than a few are likely to be in error.
Image courtesy of the American Museum of natural history and Jamie Newman.
A bit more than 100 years ago this mineralized Indian was found in a well preserved state in the Restaradora mine near Chuquicamata, Chile. He had been the victim of a mining accident. Apparently the ceiling of the narrow crawl space where he was working suddenly shifted, pinning him down and he was found hundreds of years later along with his tools--four coiled baskets, a stone hammer and a stone shovel. His arms were still extended in a working position, and one hand clutched one of the coiled baskets, which he was apparently filling with ore. During the hundreds of years he remained in the mine, prior to his discovery, he became partially mineralized and one assay run on his mummy just after he was found indicated that he was one percent copper. Shortly after his discovery arguments started over the ownership of the poor miners mummy and he was eventually sold for $15,000 (of which only $5,000 was actually paid) to two men who brought him to the United States where he was placed on display in the Chilean Pavilion at the Pan-American Exposition in Buffalo, New York. He was on display from May to November of 1901 and at one point the crowds pressing to see the mummy were so intense that his glass case was shattered. After the exhibition the mummy was offered for sale at a "fantastic price" but there were no takers. As time passed, the owners of the mummy sank into debt and the mummy was seized by a creditor. In 1905 J.P. Morgan bought the mummy and donated it to the American Museum of Natural History. The asking price for the mummy was $100,000 but most likely substantially less was paid for it. In 1923 the mummy was X-rayed and it was discovered that no bones were broken. In 1953 cores drilled in the mummy showed that the copper mineralization was only skin deep. In the late 70s parts of the body were carbon dated and the miners death was estimated to be about 484 A.D. about the same time as the fall of the Roman Empire. So if it took roughly 1500 years to change the skin of the Indian into 1% copper, it is reasonable to assume that in a million years he would most likely have become completely mineralized.1
1.Dinosaurs in the Attic: An Excursion into the American Museum of Natural History, Douglas J. Preston 1986 p.192-195.
Pseudomorph is commonly said to mean false form, meaning what you see now is a mineral that has assumed the shape of the mineral that previously existed but has been replaced by another. In reality there are a great vast number of pseudomorphs in nature. Often you have to look no further than any metamorphic rock or the matrix of the specimens your favorite crystals are growing on. Minerals form in the earth under a wide range of environments and when that environment changes, the minerals that grew in that environment usually change as well. Perhaps the pseudomorph most familiar to humans is ice after water. We all know that it forms in cold weather frequently falling from the sky in vast quantities or forming pseudomorphs in the shape of cubes in your freezer. When the conditions change, namely when warm weather or lemonade in a glass comes along the mineral changes, namely it melts and goes away. Ice after water is not the only example pictured in these articles that is a mineral after something non mineral. Included below are a number of pictures showing minerals after plants and animals. In addition to the partially mineralized man above there are pictures of Chalcocite, Copper, Fluorite, Opal and Chalcedony after wood and pyrite, turquoise, chalcedony etc. after various critters. The mineral world is chock a block full of pseudomorphs, but most of them "don't look like anything" to the casual observer, but if you study them you will come to realize that they are everywhere.
I don't think I have ever seen a transparent pseudomorph. In fact if you do see a transparent crystal that is labeled as a pseudomorph, you should be intensely skeptical that it is labeled correctly. The process of forming a pseudomorph is disruptive of the original crystal lattice, and a relatively undisturbed perfect crystal lattice is one of the requirements for crystal transparency. After you have collected pseudomorphs for a while, you can usually spot them by their sort of rough exterior. If you look through some of the images below, you will understand what I mean. Collectors of course like the pseudomorphs that are as sharp and smooth with the faces of their "crystals" as perfect and unblemished as possible but there are not many that have this degree of perfection, and of course those that do, command the highest prices. Some may contend that some metamict minerals like Zircons that have enough uranium in their structure to make them metamict can still be transparent. However I am not aware of any completely transparent zircons that are completely metamict. I am sure there are many examples out there where minerals are only partially metamict and still retain a good deal of transparency. Has anyone seen a faceted transparent zircon that is isometric, which would indicate a metamict state?
There is considerable disagreement among mineralogists and collectors about what should be considered to be a pseudomorph and what not. Some consider mineral casts after a now vanished minerals not to be pseudomorphs, but we include them here and these are generally known as casts or epimorphs. How do we know if a particular mineral has replaced another; namely is really a real pseudomorph? If we are lucky we can find examples of specimens with a crystals growing on it along with partially and completely replaced ones. When we find specimens like this we can be fairly confident that the completely replaced crystals and others like them are true pseudomorphs after the original mineral. One of the more common examples of this are azurite crystals partially or completely replaced by malachite.
The specimens whose images are presented below in the pseudomorph articles have been selected because they really "look like something". Historically pseudomorphs often didn't look like much of anything, but long study of their occurrences indicated to those studying them that what they were looking at were minerals that had replaced other minerals. However compared to the specimens shown below, many of those old pseudomorphs don't really look like something to most people. In other words, the specimens selected below are usually much more obviously pseudomorphs than what passed for pseudomorphs back in the day. Perhaps the best known historical book written on pseudomorphs was written by Blum and is called Die Pseudomorphen. It is in German, but Blum's original pseudomorph collection and a copy of his book are preserved at Yale University and if you are a causal collector of pseudomorphs, and you go and look at his specimens you think, "Are these things really pseudomorphs? They don't look like anything.
When you view the pseudomorphs in these articles you should do so with the understanding that many of them may not be accurately characterized. Many are undoubtedly correct or probably correct. There are more than just a few that should be viewed with considerable skepticism. All are interesting and I hope many will provoke research about their nature. Some of the specimens pictured below should perhaps not be here and I would welcome your comments on why they should not be included or about others that should be.
In many cases, the pseudomorphs shown in these articles are not pure minerals but rather mixtures of minerals that formed by the alteration of a preexisting mineral crystal. Perhaps the best known example of this type of pseudomorph are the ones we call limonite pseudomorphs after other minerals, perhaps most commonly limonite after Pyrite. Some of these mixture names have long historical usage and are still used today though they are not IMA approved names. We use them for want of anything better. Sometimes, only a group name is available for these pseudomorphs, like mica after something. Others are listed as Mineral A/ Mineral B mixtures after another mineral. These groups and mixture names are listed alphabetically with IMA approved mineral names and thus in these articles they have been more or less elevated to species status, but since they are not IMA approved the names the mixture name is began with a lower case letter and the group names are in Italics.
The different kinds of pseudomorphs and historical notes about them; by Kieth Harshbarger:
The term “Pseudomorphoses” was coined by the French crystallographer, the Abbe Rene Just Hauy in 1801(Traite de Mineralogie, Vol 1, pp140-5) . In his study, he believed the pseudomorph to be a type of concretion, which displayed a ‘’False or Deceitful’’ form. They were to be created through the infilling of a foreign material in the void, once occupied by another object – molds and casts. Most of his examples, dealt with preserving the shape of shells and woods. To him, a pseudomorph was more likely to represent a mineralized fossil, a concept often ignored today. He did state, however that similar things did occur in the Mineral Kingdom.
Here are the main kinds of Pseudomorphs.
Mold Pseudomorphs
A mold represents the hollow impression, resulting from the removal of the original host from a more resistant matrix. The interior wall-zone now preserves the overall shape of the original material. From those impressions, the identity of the host may be identified. They have been called solution Pseudomorphs or negative crystals.
Here are two examples of molds/solution pseudomorphs or negative crystals.
Cast pseudomorphs
A cast results from the simple infilling of any new material in the hollow mold. This thus can create a replica after the original host. Now it helps if the casts of a more resistant material than the enclosing matrix, so they may weather out for study. Called by some; Infiltration Pseudomorphs.
Here are two examples of casts/infiltration pseudomorphs.
Another slightly different hybrid case, involves two different, free-formed minerals, growing side by side. As they increase in size, they may create a common Interface. With the removal of one of the pair, an impression of the vanished species may remain on the side of the remaining crystal. The Swiss call this partial mold, a “Narben”, meaning Scar.(Frazier 2005 MSSC).
Before Hauy, Abraham Gottlob Werner, at the Freiberg Mining Academy, had a slightly different view of our subject. He divided the Mineral Kingdom into two groups: The bulk as “True Crystals “; and a smaller number which he called “Afterkristalle”(Estner 1794). Werner stated two methods by which the strange group might form. His first type resulted when an “imbedded crystal falls out and leaves an empty mold, which is afterward filled up”. This created a cast which corresponds to the shape of the Mold. His vision of the mold/cast concept featured the preservation of a mineral forn, more than just that of a fossil.
Encrustation pseudomorphs
Werner’s second method involves the deposition of another mineral over a pre-existing crystal, which afterwards may be carried away. A “crust” defining the original form is left. This is an encrustation of the true crystal. These hollow incrustation pseudomorphs often carried special names. One early term, noted more in Europe, was “perimorph”. Kenngott(1856) used this word to describe one of the divisions in his pseudomorphic classification. The perimorph was actually the coating formed by the incrustation of a mineral over a free-forned host. According to Kenngott , the original host might still remain; or could be totally removed thus creating a hollow form (See White 2003 Rocks & Minerals 78 p 348). To make matters even more interesting, He also used the concept of the “Pleromorph” to describe the infilling of the hollow Perimorph by a third mineral, unrelated to either the Host or the Crust.
Another word for this hollow pseudo type, is the ever popular “Epimorph. Betancourt(Pseudo News 1994), describes an Epimorph as a pseudo produced when a mineral forms over an earlier crystal, and the underlying mineral subsequently disappears. Frondel(1935) refers to the hollow incrustation pseudomorphs as an Epimorph. No matter what you call them: Perimorphs; Epimorphs or just Pseudomorphs, these hollow incrustations create a very interesting pseudo group.
Here are some examples of incrustation pseudomorphs/perimorphs/epimorphs.
Occasionally the Incrustation process may continue to the point of obscuring the pseudomorphic form. This may result in hollow domes, ridges or strange projecting fingers. To identify the host mineral, one must now study the interior Mold.
Another Incrustation type involves the oriented overgrowth of small crystals on a free-formed mineral. The first species stops growing, but now acts as the host for a new generation of a different material, which now defines and enlarges the original form. This could result in the host being totally removed, to form an oriented epimorph, where some original material may still remain. Good examples of this are the nice oriented patterns of Arsenopyrite in these examples.
Substitution pseudomorphs
A student of Werner, added the next major Pseudo Category. August Beithaupt(1815) wrote “On the Authenticity of Crystals. He decribed the difference between “True Crystals” and the two types of “Afterkristalle”, as noted by Werner. He equated the term Afterkrystal with Pseudomorph of Hauy. But he also added a third method by which False Forms could be created. He called the new process “ Metamorphischen”. This is now often refered to as Metasomatic Replacement. It involves the simultaneous, volume for volume, non chemical, replacement of the host, by a new material. Due to the exact nature of the process, the resulting Pseudomorphs are usually very sharp, solid forms, which may preserve striations, and other surface features, displayed by the original crystal. Most classifications simply refer to them as replacement or substitution Pseudomorphs.
Here are some examples of replacement or substitution pseudomorphs.
Alteration pseudomorphs
A large section in the literature refer to Alteration Pseudomorphs. This envolves a structural or Chemical changes, which actually take place within the body of the host crystal. One such study was by Haidinger(1827). His first group delt with “Changes in substances having the same composition”. This is one type of Structural alteration. Dana(1845) called this class “Allomorphs”. But in the same year, Stein(1845) coined the term now generally used paramorph. A paramorph is a structural pseudomorph, formed between minerals with the same chemical composition. This is usually triggered by environmental temperature/pressure changes in the deposit.
There are two types of paramorphs. The first (monotropic) involves a minor change within the crystal structure. High-Quartz is stable above 573 degrees. However as it cools down below that level, a slight shift in the position of the silica atom, converts the crystal into a milky white Paramorph of Low-Quartz. In theory, The paramorph can be reheated to reform the High-Quartz crystal.
The second divison contains non-enantropic structural alterations. A single aragonite crystal often is converted into a granular calcite paramorph. As the internal structure of the Aragonite was destroyed, the original material can not be recreated. Another group now has the shape of the host, being defined by an oriented network of small crystals of a more stable member of the same chemical set. Here is an example of this.
Rutile often forms good oriented Paramorphs after both Anatase and Brookite. Here are two classical examples of these.
Uralite pseudomorphs
Scheerer(1854 Paramorphismus) published an expanded vision of the paramorph. In his work, he included a group of pseudomorphs, now called “Uralites”. This involved the conversion of a pyroxene (a single-chain silicate), into an amphibole (a double-chain silicate). This can result in crystals of Diopside altering into parallel fibers of Actinolite/Tremolite but retaining the original form of the Diopside crystal. While this indeed was a structural alteration, to make it work, there also had to be a chemical interchange (magnesium for calcium etc.). Thus is a hybrid pseudomorph, due to both a structural and a chemical alteration. Here is an example of a uralite pseudomorph.
Exsolution
Exsolution results from the unmixing or decomposition of a High Temperature Mineral during cooling. This generally overlooked pseudomorphic type was first noted by Pelikan(1902 Tschermarks Mineralogische XXI). He was studing a Swiss Ilmanite, Whose shape, under magnification, was now preserved by an oriented intergrowth of Rutile laths and tiny octahedral of Magnetite. He considered this to be a pseudomorph due to Unmixing.
Example: Hematite & Rutile After Ilmanite Mwinilunga, Zambia No photo.
Decomposition pseudomorphs
These are another exsolution type of pseudomorph. Some high temperature Leucite crystals, upon rapid cooling, separate out into a composite pseudomorph of Orthoclase and Nepheline, now called “Pseudoleucite”. The exterior may be composed of fine grained Orthoclase, but the next layer produces an elongated lath-like structure of Orthoclase and Nephaline, in parallel position, to create a “Palisade Structure”. The core may contain a fine-grained mixture of several minerals.
Examples: Orthoclase & Nepheline after Leucite from, Kamam-Kalehövük, Kırşehir Province, Central Anatolia Region, Turkey and Loučná, Ostrov, Krušné Hory Mts (Erzgebirge), Karlovy Vary Region, Bohemia (Böhmen; Boehmen), Czech Republic
[Metamict pseudomorphs]
The structural disintegration of minerals into a glass like state caused by alpha radiation emitted from the decay of uranium and thorium atoms in the structure of the mineral, has been known for quite some time. Such Metamict crystals have not been included in lists of pseudomorphic types until quite recently. Mitchell (Metamict Minerals, MR 4,1973, p 177), in his review noted, “These noncrystalline pseudomorphs often retain their crystal faces”. But it was Strunz (Pseudomorphosen, Der Aufschluss, 33, 1982, 319), who considered them to be a “Splinter” Group of the Paramorph. Betafite crystals often display sharp yellow-brown altered faces but the amorphous material within the interior, could not now, create those faces. Thus some believe that such crystal forms, to be a false form or a pseudomorph.
Examples
[Kieth Harshbarger 2012]
Where did our images below come from?
These images below and those in the other Best Minerals articles on pseudomorphs were originally chosen from the Mindat's general image gallery by searching the image captions for the word "after". There were thousands to sort through and select. Then the captions were searched for the words "replaced" and "replacing". These key words turned up another horde of pseudomorphs. Then searching on the key works "altered" and "altering" added yet more. It is likely that still other pseudomorphs lurk in our database that are not included in the examples we show. If you find any of these it would be appreciated if you could bring them to our attention.
[Rock Currier 2011]
Useful notes
1. IMA approved mineral names have their first letter capitalized.
2. Group names have their first letter capitalized and are in Italic font.
3. Mixture names like limonite are all in lower case letters.
4. FOV stands for field of view or the width of the image.
5. @ is sometimes used as an abbreviation for the word after, when the caption needs to be shortened for cosmetic purposes.
6. w is sometimes used as an abbreviation for the word with, when the caption needs to be shortened for cosmetic purposes.
7. Often times there is more information about the specimen in the caption field of the full image. To see the full caption and/or to view the enlarged image of the specimen, click on the picture and it will open to a full window.
8. The symbol ~ is used in some captions to indicate an approximate size.
9. Opal and chalcedony pseudomorphs are in the article on Quartz pseudomorphs.
[Rock Currier 2011]
Acanthite is the most common silver mineral and probably occurs in every silver mine in the world. It is a black mineral, but it is a black mineral made up mostly of silver! That makes all the difference in the world in the eyes of collectors. If you don’t think that’s true, ask around and see if you can find even one collector who would rather have a good augite instead of a good acanthite. What? You don’t even have an augite in your collection? You don’t even know what augite is? That’s ok, I understand. I am not a big fan of Augites either.
In years past the black isometric looking crystals of silver sulfide were called argentite and were thought to be different in structure from the little pointy crystals of silver sulfide, thought to be orthorhombic, that were called acanthite. By the 1920s, it was becoming obvious that this was not the case. Ramsdele at the University of Michigan1 pointed out that angle measurements of argentite crystals were not those of isometric crystals and showed that the x-ray diffraction pattern of argentite and acanthite were the same. He speculated that argentite and a few other minerals of the galena group might be isometric only at high temperatures. Emmons, Stockwell & Jones2 showed that this was the case and that the inversion temperature of Acanthite was about 180° C. That left only acanthite standing as a valid species at room temperature so now curators and collectors needed to go and change the labels on all their Argentite specimens. On many specimens the label changes were not made and you will still see many specimens labeled argentite in old collections. The correct label for isometric looking crystals of silver sulfide could read Acanthite pseudomorph after argentite. Since some mineralogists don’t recognize argentite to be a valid mineral species because it does not exist at room temperature they would want to see these specimens labeled simply Acanthite. It all depends on what you definition of a mineral is. Yes, people are still arguing about that and every mineralogist worth his salt has a slightly different opinion.
Most Acanthite pseudomorphs after argentite crystals are not very shiny, but some of the newer specimens from the Rayes mine (not Reyes) are quite lustrous. I suspect that like many other sulfide minerals, after fifty or a hundred years, their surfaces will react with oxygen, ozone and other crud in the atmosphere and at least their surface chemistry will change and they will lose their luster. Crystals of about 4 cm are known but the best specimens have smaller crystals. Crystals of 2 cm are considered large. Most specimens of Acanthite are in the 5 cm and smaller range. Larger fine specimens are rare. The best specimens of this mineral are less than 18 cm in size with sharp crystals of 1.25 cm or larger. Historically, the best specimens came from Germany and Mexico. During the last twenty years the Rayes mine at Guanajuato has weighed in again with some very fine acanthites.
Fine Acanthite pseudomorphs after argentite are infrequently seen in a dealer’s stock and then perhaps as only a specimen or two. I don’t think I have ever seen a full flat of really fine acanthites except once in the inventory of Dave Bunk of Denver Colorado. Only in great museums collections are you likely to see more than one or two fine pieces. Occasionally a collector specializing in silver minerals may have several fine pieces in a drawer full of acanthite specimens, but it probably took him a lifetime to hunt them down. A fine thumbnail size acanthite specimen will probably cost you two to five hundred dollars and a good miniature or small cabinet specimen can run thousands of dollars.
Because acanthite is a black mineral it is not easily seen in dark places like smoke filled stopes; many fabulous specimens have gone unseen, ground through mills and turned into coins. Stories of miners and dealers selling fabulous acanthite specimens for a song because they were thought to be low grade galena specimens are urban legends in the collecting community. In many silver mines acanthite has been the main ore or a major ore component and many tons of fine specimen, certainly vastly more than were saved, have been lost to the smelters.
[Rock Currier, 27 December 2008]
Acanthite after Argentite
Germany
Saxony, Erzgebirge, Freiberg District
Acanthite after Argentite
Mexico
Guanajuato
Acanthite after Argentite
Mexico
Guanajuato, Mun. de Guanajuato, Guanajuato, San Juan de Rayas Mine (Rayas Mine; Reyes Mine)
Acanthite after Argentite
Morocco
Souss-Massa-Draâ Region, Ouarzazate Province, Djebel Saghro (Jbel Saghro), Imiter District, Imiter Mine
Acanthite after Polybasite
Mexico
Guanajuato, Mun. de Guanajuato, Guanajuato
Acanthite after Silver
China
Anhui Province, Chaohu Prefecture, Lujiang Co.
Acanthite after Stephanite
Mexico
Zacatecas, Mun. de Fresnillo, Fresnillo de Gonzalez Echeverria (Fresnillo)
Adamite after Legrandite
Mexico
Durango, Mun. de Mapimí, Mapimí, Ojuela Mine
Albite after Analcime
Norway
Akershus, Lørenskog, Feiring Bruk
Albite after Calcite
Norway
Vestfold, Re, Flår
Albite after Scapolite
Canada
Ontario, Renfrew Co., Greater Madawaska Township, Griffith, Khartum
Amphabole after Aegirine
Malawi
Zomba District, Mt. Malosa
Analcime after Analcime & Siderite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Only a handful of these unusual pseudomorphs have been found. St Hilaire has produced many very unusual pseudomorphs and you will see quite a variety of them in these articles.
Analcime after Burbankite?
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Anclcime after Cancrinite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Analcime after Laumontite
UK
Scotland, Strathclyde (Dunbartonshire), Inverclyde, Kilmacolm, Auchenbothie
Laumontite is a very unstable mineral that dehydrated rapidly when exposed to the air. Few of them last more than a few years unless great care has been taken to preserve them and even those that have often show the ravages of slow decomposition. Here we see an example of Laumontite that has been altered to Analcime.
Analcime after Laumontite
USA
Michigan, Keweenaw Co., Copper Falls
Analcime after Natrolite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Anatase after Perovskite and Magnetite
USA
Arkansas, Hot Spring Co., Magnet Cove, Perovskite Hill
Anatase after Titanite
Canada
Ontario, Haliburton Co., Monmouth Township, Tory Hill, Bear Lake diggings (Gibson Road Western occurrence)
Anatase after Titanite
USA
North Carolina, Henderson Co., Zirconia (Tuxedo Station), Jones Mine
Anatase after Titanite
USA
Texas, Llano Co., Llano, Badu Hill pegmatite
Andradite after Rhodochrosite
South Africa
Northern Cape Province, Kalahari manganese fields, Hotazel, Wessels Mine (Wessel's Mine)
Anglesite after Cerussite
Australia
New South Wales, Yancowinna Co., Broken Hill
Anglesite pseudomorphs after Cerussite were quite common when these famous mines were producing, but they are not particularly attractive and that is probably why large quantities of them were not saved. Even so, you can still find them occasionally offered for sale today.
Anglesite after Cerussite
Namibia
Otjikoto (Oshikoto) Region, Tsumeb, Tsumeb Mine (Tsumcorp Mine)
Anglesite after Galena with Sulfur
Poland
Upper Silesia (Slaskie), Upper Silesian Coal Basin, Rybnik Coal Area, Rybnik, Ignacy-Hoym coal mine
Anglesite after Galena
USA
New Mexico, Socorro Co., Hansonburg District, Bingham, Blanchard Mine (Portalas-Blanchard Mine)
Specimens of Anglesite pseudomorphs after Galena were quite common in the Blanchard and its sister mines at Bingham and you could collect them on every trip there if you wanted to. But they are not particularly attractive compared to the fluorite and other copper minerals like Brochantite, Linarite and Scorodite upon which collectors tended to concentrate. Frequently these galena crystals are only altered a bit on the outside and still retain much of the Galena in the "centers" of the crystals. But as generations of collectors and small mining have worked the deposit, good specimens from there are becoming harder to get. Perhaps at some time, if lead and copper become valuable enough the entire deposit will be open pitted and large quantities of specimens will once again be available.
Rock Currier 2011]
Anglesite after Linarite
UK
Wales, Ceredigion (Dyfed; Cardiganshire), Ceulanymaesmawr, Talybont, Nant-y-Moch Reservoir area, Eaglebrook Mine (Nant-Y-Cagel Mine; Nantycagl Mine; Nantygagal Mine; Dolrhyddlan Mine)
Anhydrite after Anhydrite
Italy
Tuscany, Grosseto Province, Montieri, Campiano Mine
Ankerite & Albite after Aegirine & Analcime
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Ankerite after Barite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nent Valley, Nentsberry Haggs Mine
Ankerite after Calcite
France
Alsace, Haut-Rhin, Ste Marie-aux-Mines (Markirch), Neuenberg
It is deffinately ankerite after calcite. Many test where done on these and the more recently by Fluck and Bari in 1982 and later on. These are well known in the district for several centuries. They are part of the " paragenèse à carbonates nobles " (noble carbonates paragenesis) which is the paragenesis of the veins. The native silver and silver minerals from the district were always found near these pockets and with this paragenesis. At the museum at Ste Marie there is(was ?) a chalcopyrite crystal cluster with these doubly terminated pseudo's to 6 cm cris-cross over them. I saw that piece back in 78 and still dreaming about it.
What I find interesting about these pseudo's is that the original form of calcite ( the scalenohedron ) nearly completely dissapeared from the district except from 2 mines ( according to my observations of the specimens in many local collections and books on the district). All other calcite crystals were formed later, is of the " joplin" type or simple rhombs. The scalenohedron is observed in the Toussaint mine and in the Glück Auf (see my gallery). I saw in 1987, in a local collection, a double terminatated pseudo af ankerite after calcite on matrix sparkled with very tiny gemmy double terminated joplin calcites. Just amazing. The collection has been dispersed whem the owner passed away in that same year. I have no idea where the specimen went. It would be great to locate that piece back and take a pic of it for Mindat.
[Paul De Bondt 2011]
Annabergite after Millerite?
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nenthead, Smallcleugh Mine
Antigorite after Monticellite
Italy
Trentino-Alto Adige, Trento Province, Fassa Valley
Apatite after Wagnerite
Norway
Telemark, Bamble (Bamle), Havredal (Hafredal), Nedre Havredal, The Kjerulfine mine
Aragonite after ? with Sulfur
Italy
Sicily, Agrigento Province
Aragonite after Calcite?
Namibia
Otjikoto (Oshikoto) Region, Tsumeb
Arfvedsonite after Aegirine
Malawi
Zomba District, Mt Malosa
Arsenogoyazite after Cuprite?
Germany
Baden-Württemberg, Black Forest, Wolfach, Oberwolfach, Rankach valley, Clara Mine
These are more likely to be after scorrodite than cuprite.
Arsenopyrite after Pyrrhotite?, Sphalerite & Calcite
Kosovo
Kosovska Mitrovica, Trepca valley, Trepca complex, Stari Trg Mine
Arsenopyrite after Pyrrhotite
Mexico
Chihuahua, Mun. de Aquiles Serdán, Santa Eulalia District
Arsenopyrite after Pyrrhotite
Peru
Huánuco Department, Dos de Mayo Province, Huallanca District, Huanzala Mine
Arsenopyrite after Pyrrhotite
USA
South Dakota, Lawrence Co., Galena District, Deadwood, Double Rainbow Mine (Richmond Sitting Bull)
Atacamite? after Rat
Russia
(unknown)
The specimen is in a display case in the Fersman Museum in Moscow, Russia and is labeled as Atacamite. Its not a very big rat and perhaps it might be better described as a mineralized mouse. Inquiries as to the provenence of the mouse/specimen indicates that the specimen is from an unknown locality and that it might not be after atacamite, but perhaps Chalcanthite. In fact there is speculation that the origin of the specimen might be a chemical laboratory or chemical production facility where the mouse was poisoned by the chemicals and died. I suspect that the specimen is such a big tourist attraction is the reason that it is left on display.
Augite after Monticellite
Italy
Trentino-Alto Adige, Trento Province, Fassa Valley, Monzoni Mts, Toal de la Foia
Azurite after Calcite
Greece
Attikí (Attica; Attika) Prefecture, Lavrion (Laurion; Laurium) District, Lavrion District Mines
Azurite after Chalcostibite
Morocco
Grand Casablanca Region, Casablanca Prefecture, Cherrat Wadi, Rar-el-Anz
Azurite after Cuprite
France
Rhône-Alpes, Rhône, Chessy-les-Mines
These pseudomorphs are exceptionally rare. I have only seen perhaps a half dozen of them and this was the best one to my knowledge, but certainly there must be as good or better in France somewhere. This was in the collection of Arthur Montgomery and he had three of them. He gave me his second best one and I have cherished it for many years. Arthur came to believe that possessions were a barrier that prevented spiritual progress and he eventually gave away all of his extremely fine collection to institutions and young collectors. He said "would you like some specimens? " I was so surprised I could hardly speak. He then would indicate some of the specimens you might choose from. And when I pointed to one of these pseudomorphs he said "Can you get those any more". "No Dr. Montgomery, you can't get those anymore." For every one of these azurite after cuprite, there were hundreds if not thousands of malachite pseudomorphs after cuprite produced.
[Rock Currier 2011]
Azurite after Tetrahedrite
France
Midi-Pyrénées, Ariège, Irazein
This is really an incredible specimen. It is in the collection of University of Paris (Sorbonne). Pierre Bariand, curator of the museum told me how he got the specimen for the museum. He got a call that a French school was getting rid of its collection and that he wanted any of the specimens he should come and take them. When he arrived, there was a pile of minerals/rocks on the floor and sitting on the top was this specimen. Crystals of tetrahedrite of this size are almost unheard of and the fact that this one, altered though it might be, appears to be a floater with no visible point of attachment makes it all the more amazing.
Azurite after wood
USA
Arizona, Cochise Co., Mule Mts, Warren District, Bisbee
Baryite after Calcite
Morocco
Meknès-Tafilalet Region, Er Rachidia Province, Taouz
Barite after Celestine
USA
Illinois, Hardin Co., Illinois - Kentucky Fluorspar District, Harris Creek Sub-District, Annabel Lee mine
Baryte after Fluorite on Ferberite
Kazakhstan
Karagandy Province (Qaragandy Oblysy; Karaganda Oblast'), Betpakdala Desert (Bet-Pak-Dal Desert), Kara-Oba W deposit
Barite after Witherite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District
Barite after Witherite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nent Valley, Nentsberry Haggs Mine
Barite after Witherite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nenthead, Rampgill Mine
Bastnäsite-(Ce) after Petersenite-(Ce)? & Rhodochrosite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Bastnäsite-(Ce) after Sazhinite-(Ce)?
Namibia
Khomas Region, Windhoek District, Windhoek, Aris, Aris Quarries (Ariskop Quarry; Railway Quarry)
Bavenite afer Beryl
Austria
Salzburg, Hohe Tauern Mts, Obersulzbach valley
Bavenite after Beryl
Norway
Aust-Agder, Evje og Hornnes, Li Quarry (Liheia)
Bayldonite after Mimetite
Namibia
Otjikoto (Oshikoto) Region, Tsumeb, Tsumeb Mine (Tsumcorp Mine)
Betekhtinite after Bornite
Kazakhstan
Karagandy Province (Qaragandy Oblysy; Karaganda Oblast'), Dzhezkazgan (Zhezqazghan), Dzhezkazgan Mine (Zhezqazghan Mine)
Bicchulite & Hydrogrossularite after Gehlenite
Japan
Honshu Island, Chugoku Region, Okayama Prefecture, Takahashi, Bitchu-cho (Bicchu-cho), Fuka mine
Birnessite/Ranciéite after Serandite
Canada
Québec, Montérégie, Lajemmerais RCM, Varennes & St-Amable, Saint-Amable sill, Demix-Varennes quarry
Bismoclite after Bismuthinite, Quartz & Clinochlore
UK
England, Cornwall, Mount's Bay District, St Hilary, Croft Gothal Mine
Bismutite after Bismuthinite
USA
New Mexico, Hidalgo Co., Apache No. 2 District, Anderson-Apache mine
Bornite after Chalcocite on Quartz
UK
England, Cornwall, St Just District, St Just, Trewellard, Levant Mine
Bornite after Chalcocite
USA
Wisconsin, Rusk Co., Ladysmith, Flambeau Mine
Brochantite after Langite
Austria
Salzburg, Hohe Tauern Mts, Kaprun valley, Kaprun, Lechnerberg Mt. (slag locality)
Brockite after Microlite
USA
Virginia, Amelia Co., Winterham, Morefield Mine (Morefield Pegmatite)
Bulfonteinite after Apophyllite on Calcite
South Africa
Northern Cape Province, Kalahari manganese fields, Kuruman, N'Chwaning Mines, N'Chwaning II Mine
Click here to view Pseudomorphs & Replacements C. Click here to view Pseudomorphs & Replacements D to I. Click Here to view Pseudomorphs & Replacements J to M. Click here to view Pseudomorphs & Replacements N to P. Click here to view Pseudomorphs & Replacements Quartz. Click here to view Pseudomorphs & Replacements R to Z. Click here to view Best Minerals P, click here to view and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Images last selected December 2010 sorting on: after, altered, altering, replaced & replacing
Rock Currier
Crystals not pistols.
Edited 107 time(s). Last edit at 11/25/2012 03:03AM by Rock Currier.
Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?
I don't think I have ever seen so many minerals in one place with captions containing so many question marks, Possibles, Presumablies, Probables, Seems to bees, Unknowns, Could bees, Maybes and Yet to be determineds. And of those images that don't have one of the forgoing qualifiers, certainly more than a few are likely to be in error.
Image courtesy of the American Museum of natural history and Jamie Newman.
A bit more than 100 years ago this mineralized Indian was found in a well preserved state in the Restaradora mine near Chuquicamata, Chile. He had been the victim of a mining accident. Apparently the ceiling of the narrow crawl space where he was working suddenly shifted, pinning him down and he was found hundreds of years later along with his tools--four coiled baskets, a stone hammer and a stone shovel. His arms were still extended in a working position, and one hand clutched one of the coiled baskets, which he was apparently filling with ore. During the hundreds of years he remained in the mine, prior to his discovery, he became partially mineralized and one assay run on his mummy just after he was found indicated that he was one percent copper. Shortly after his discovery arguments started over the ownership of the poor miners mummy and he was eventually sold for $15,000 (of which only $5,000 was actually paid) to two men who brought him to the United States where he was placed on display in the Chilean Pavilion at the Pan-American Exposition in Buffalo, New York. He was on display from May to November of 1901 and at one point the crowds pressing to see the mummy were so intense that his glass case was shattered. After the exhibition the mummy was offered for sale at a "fantastic price" but there were no takers. As time passed, the owners of the mummy sank into debt and the mummy was seized by a creditor. In 1905 J.P. Morgan bought the mummy and donated it to the American Museum of Natural History. The asking price for the mummy was $100,000 but most likely substantially less was paid for it. In 1923 the mummy was X-rayed and it was discovered that no bones were broken. In 1953 cores drilled in the mummy showed that the copper mineralization was only skin deep. In the late 70s parts of the body were carbon dated and the miners death was estimated to be about 484 A.D. about the same time as the fall of the Roman Empire. So if it took roughly 1500 years to change the skin of the Indian into 1% copper, it is reasonable to assume that in a million years he would most likely have become completely mineralized.1
1.Dinosaurs in the Attic: An Excursion into the American Museum of Natural History, Douglas J. Preston 1986 p.192-195.
Pseudomorph is commonly said to mean false form, meaning what you see now is a mineral that has assumed the shape of the mineral that previously existed but has been replaced by another. In reality there are a great vast number of pseudomorphs in nature. Often you have to look no further than any metamorphic rock or the matrix of the specimens your favorite crystals are growing on. Minerals form in the earth under a wide range of environments and when that environment changes, the minerals that grew in that environment usually change as well. Perhaps the pseudomorph most familiar to humans is ice after water. We all know that it forms in cold weather frequently falling from the sky in vast quantities or forming pseudomorphs in the shape of cubes in your freezer. When the conditions change, namely when warm weather or lemonade in a glass comes along the mineral changes, namely it melts and goes away. Ice after water is not the only example pictured in these articles that is a mineral after something non mineral. Included below are a number of pictures showing minerals after plants and animals. In addition to the partially mineralized man above there are pictures of Chalcocite, Copper, Fluorite, Opal and Chalcedony after wood and pyrite, turquoise, chalcedony etc. after various critters. The mineral world is chock a block full of pseudomorphs, but most of them "don't look like anything" to the casual observer, but if you study them you will come to realize that they are everywhere.
I don't think I have ever seen a transparent pseudomorph. In fact if you do see a transparent crystal that is labeled as a pseudomorph, you should be intensely skeptical that it is labeled correctly. The process of forming a pseudomorph is disruptive of the original crystal lattice, and a relatively undisturbed perfect crystal lattice is one of the requirements for crystal transparency. After you have collected pseudomorphs for a while, you can usually spot them by their sort of rough exterior. If you look through some of the images below, you will understand what I mean. Collectors of course like the pseudomorphs that are as sharp and smooth with the faces of their "crystals" as perfect and unblemished as possible but there are not many that have this degree of perfection, and of course those that do, command the highest prices. Some may contend that some metamict minerals like Zircons that have enough uranium in their structure to make them metamict can still be transparent. However I am not aware of any completely transparent zircons that are completely metamict. I am sure there are many examples out there where minerals are only partially metamict and still retain a good deal of transparency. Has anyone seen a faceted transparent zircon that is isometric, which would indicate a metamict state?
There is considerable disagreement among mineralogists and collectors about what should be considered to be a pseudomorph and what not. Some consider mineral casts after a now vanished minerals not to be pseudomorphs, but we include them here and these are generally known as casts or epimorphs. How do we know if a particular mineral has replaced another; namely is really a real pseudomorph? If we are lucky we can find examples of specimens with a crystals growing on it along with partially and completely replaced ones. When we find specimens like this we can be fairly confident that the completely replaced crystals and others like them are true pseudomorphs after the original mineral. One of the more common examples of this are azurite crystals partially or completely replaced by malachite.
The specimens whose images are presented below in the pseudomorph articles have been selected because they really "look like something". Historically pseudomorphs often didn't look like much of anything, but long study of their occurrences indicated to those studying them that what they were looking at were minerals that had replaced other minerals. However compared to the specimens shown below, many of those old pseudomorphs don't really look like something to most people. In other words, the specimens selected below are usually much more obviously pseudomorphs than what passed for pseudomorphs back in the day. Perhaps the best known historical book written on pseudomorphs was written by Blum and is called Die Pseudomorphen. It is in German, but Blum's original pseudomorph collection and a copy of his book are preserved at Yale University and if you are a causal collector of pseudomorphs, and you go and look at his specimens you think, "Are these things really pseudomorphs? They don't look like anything.
When you view the pseudomorphs in these articles you should do so with the understanding that many of them may not be accurately characterized. Many are undoubtedly correct or probably correct. There are more than just a few that should be viewed with considerable skepticism. All are interesting and I hope many will provoke research about their nature. Some of the specimens pictured below should perhaps not be here and I would welcome your comments on why they should not be included or about others that should be.
In many cases, the pseudomorphs shown in these articles are not pure minerals but rather mixtures of minerals that formed by the alteration of a preexisting mineral crystal. Perhaps the best known example of this type of pseudomorph are the ones we call limonite pseudomorphs after other minerals, perhaps most commonly limonite after Pyrite. Some of these mixture names have long historical usage and are still used today though they are not IMA approved names. We use them for want of anything better. Sometimes, only a group name is available for these pseudomorphs, like mica after something. Others are listed as Mineral A/ Mineral B mixtures after another mineral. These groups and mixture names are listed alphabetically with IMA approved mineral names and thus in these articles they have been more or less elevated to species status, but since they are not IMA approved the names the mixture name is began with a lower case letter and the group names are in Italics.
The different kinds of pseudomorphs and historical notes about them; by Kieth Harshbarger:
The term “Pseudomorphoses” was coined by the French crystallographer, the Abbe Rene Just Hauy in 1801(Traite de Mineralogie, Vol 1, pp140-5) . In his study, he believed the pseudomorph to be a type of concretion, which displayed a ‘’False or Deceitful’’ form. They were to be created through the infilling of a foreign material in the void, once occupied by another object – molds and casts. Most of his examples, dealt with preserving the shape of shells and woods. To him, a pseudomorph was more likely to represent a mineralized fossil, a concept often ignored today. He did state, however that similar things did occur in the Mineral Kingdom.
Here are the main kinds of Pseudomorphs.
Mold Pseudomorphs
A mold represents the hollow impression, resulting from the removal of the original host from a more resistant matrix. The interior wall-zone now preserves the overall shape of the original material. From those impressions, the identity of the host may be identified. They have been called solution Pseudomorphs or negative crystals.
Here are two examples of molds/solution pseudomorphs or negative crystals.
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| Quartz @ Glauberite, Paterson, NJ, USA ~6cm | © EAS 2009 |
Cast pseudomorphs
A cast results from the simple infilling of any new material in the hollow mold. This thus can create a replica after the original host. Now it helps if the casts of a more resistant material than the enclosing matrix, so they may weather out for study. Called by some; Infiltration Pseudomorphs.
Here are two examples of casts/infiltration pseudomorphs.
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| Quartz @ Halite, Yavapai Co. USA~5cm | © |
Another slightly different hybrid case, involves two different, free-formed minerals, growing side by side. As they increase in size, they may create a common Interface. With the removal of one of the pair, an impression of the vanished species may remain on the side of the remaining crystal. The Swiss call this partial mold, a “Narben”, meaning Scar.(Frazier 2005 MSSC).
Before Hauy, Abraham Gottlob Werner, at the Freiberg Mining Academy, had a slightly different view of our subject. He divided the Mineral Kingdom into two groups: The bulk as “True Crystals “; and a smaller number which he called “Afterkristalle”(Estner 1794). Werner stated two methods by which the strange group might form. His first type resulted when an “imbedded crystal falls out and leaves an empty mold, which is afterward filled up”. This created a cast which corresponds to the shape of the Mold. His vision of the mold/cast concept featured the preservation of a mineral forn, more than just that of a fossil.
Encrustation pseudomorphs
Werner’s second method involves the deposition of another mineral over a pre-existing crystal, which afterwards may be carried away. A “crust” defining the original form is left. This is an encrustation of the true crystal. These hollow incrustation pseudomorphs often carried special names. One early term, noted more in Europe, was “perimorph”. Kenngott(1856) used this word to describe one of the divisions in his pseudomorphic classification. The perimorph was actually the coating formed by the incrustation of a mineral over a free-forned host. According to Kenngott , the original host might still remain; or could be totally removed thus creating a hollow form (See White 2003 Rocks & Minerals 78 p 348). To make matters even more interesting, He also used the concept of the “Pleromorph” to describe the infilling of the hollow Perimorph by a third mineral, unrelated to either the Host or the Crust.
Another word for this hollow pseudo type, is the ever popular “Epimorph. Betancourt(Pseudo News 1994), describes an Epimorph as a pseudo produced when a mineral forms over an earlier crystal, and the underlying mineral subsequently disappears. Frondel(1935) refers to the hollow incrustation pseudomorphs as an Epimorph. No matter what you call them: Perimorphs; Epimorphs or just Pseudomorphs, these hollow incrustations create a very interesting pseudo group.
Here are some examples of incrustation pseudomorphs/perimorphs/epimorphs.
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| Quartz @ Calcite, Ouray, Colorado 4.2cm | © Lavinsky |
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| Back side of left | © Rob Lavinsky |
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| Pyrite @ anhydrite, Reynolds Co. USA 5cm | © Weinrich |
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| Back side of left | © Weinrich |
Occasionally the Incrustation process may continue to the point of obscuring the pseudomorphic form. This may result in hollow domes, ridges or strange projecting fingers. To identify the host mineral, one must now study the interior Mold.
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| Bottom view of left | © Lavinsky |
Another Incrustation type involves the oriented overgrowth of small crystals on a free-formed mineral. The first species stops growing, but now acts as the host for a new generation of a different material, which now defines and enlarges the original form. This could result in the host being totally removed, to form an oriented epimorph, where some original material may still remain. Good examples of this are the nice oriented patterns of Arsenopyrite in these examples.
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| Another one 8.3cm | © Lavinsky |
Substitution pseudomorphs
A student of Werner, added the next major Pseudo Category. August Beithaupt(1815) wrote “On the Authenticity of Crystals. He decribed the difference between “True Crystals” and the two types of “Afterkristalle”, as noted by Werner. He equated the term Afterkrystal with Pseudomorph of Hauy. But he also added a third method by which False Forms could be created. He called the new process “ Metamorphischen”. This is now often refered to as Metasomatic Replacement. It involves the simultaneous, volume for volume, non chemical, replacement of the host, by a new material. Due to the exact nature of the process, the resulting Pseudomorphs are usually very sharp, solid forms, which may preserve striations, and other surface features, displayed by the original crystal. Most classifications simply refer to them as replacement or substitution Pseudomorphs.
Here are some examples of replacement or substitution pseudomorphs.
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| Quartz @ aragonite, Chubut, Argentina 5cm | © Lodovichi |
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| Quartz @ Barite, Moab, Utah 2.8cm | © Rob Lavinsky |
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| Quartz after fluorite, Trestia, Romania 5.2cm wide | © |
Alteration pseudomorphs
A large section in the literature refer to Alteration Pseudomorphs. This envolves a structural or Chemical changes, which actually take place within the body of the host crystal. One such study was by Haidinger(1827). His first group delt with “Changes in substances having the same composition”. This is one type of Structural alteration. Dana(1845) called this class “Allomorphs”. But in the same year, Stein(1845) coined the term now generally used paramorph. A paramorph is a structural pseudomorph, formed between minerals with the same chemical composition. This is usually triggered by environmental temperature/pressure changes in the deposit.
There are two types of paramorphs. The first (monotropic) involves a minor change within the crystal structure. High-Quartz is stable above 573 degrees. However as it cools down below that level, a slight shift in the position of the silica atom, converts the crystal into a milky white Paramorph of Low-Quartz. In theory, The paramorph can be reheated to reform the High-Quartz crystal.
The second divison contains non-enantropic structural alterations. A single aragonite crystal often is converted into a granular calcite paramorph. As the internal structure of the Aragonite was destroyed, the original material can not be recreated. Another group now has the shape of the host, being defined by an oriented network of small crystals of a more stable member of the same chemical set. Here is an example of this.
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| Calcite @ aragonite, Larimer Co. Colorado USA 7cm | © DSW 2011 |
Rutile often forms good oriented Paramorphs after both Anatase and Brookite. Here are two classical examples of these.
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| Rutile @ anatase, Brazil 2.4cm | © Bracke |
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| Rutile @ brookite, Magnet Cove, AK USA 5.7cm | © |
Uralite pseudomorphs
Scheerer(1854 Paramorphismus) published an expanded vision of the paramorph. In his work, he included a group of pseudomorphs, now called “Uralites”. This involved the conversion of a pyroxene (a single-chain silicate), into an amphibole (a double-chain silicate). This can result in crystals of Diopside altering into parallel fibers of Actinolite/Tremolite but retaining the original form of the Diopside crystal. While this indeed was a structural alteration, to make it work, there also had to be a chemical interchange (magnesium for calcium etc.). Thus is a hybrid pseudomorph, due to both a structural and a chemical alteration. Here is an example of a uralite pseudomorph.
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| "Uralite" @ Augite, Alaska 4cm | © Betts |
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| Tremolite @ Diopside, Norway 11cm | © Nunes |
Exsolution
Exsolution results from the unmixing or decomposition of a High Temperature Mineral during cooling. This generally overlooked pseudomorphic type was first noted by Pelikan(1902 Tschermarks Mineralogische XXI). He was studing a Swiss Ilmanite, Whose shape, under magnification, was now preserved by an oriented intergrowth of Rutile laths and tiny octahedral of Magnetite. He considered this to be a pseudomorph due to Unmixing.
Example: Hematite & Rutile After Ilmanite Mwinilunga, Zambia No photo.
Decomposition pseudomorphs
These are another exsolution type of pseudomorph. Some high temperature Leucite crystals, upon rapid cooling, separate out into a composite pseudomorph of Orthoclase and Nepheline, now called “Pseudoleucite”. The exterior may be composed of fine grained Orthoclase, but the next layer produces an elongated lath-like structure of Orthoclase and Nephaline, in parallel position, to create a “Palisade Structure”. The core may contain a fine-grained mixture of several minerals.
Examples: Orthoclase & Nepheline after Leucite from, Kamam-Kalehövük, Kırşehir Province, Central Anatolia Region, Turkey and Loučná, Ostrov, Krušné Hory Mts (Erzgebirge), Karlovy Vary Region, Bohemia (Böhmen; Boehmen), Czech Republic
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| Pseudoleucite @ Leucite 7.2cm, Turkey | © DSW |
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| "Pseudoleucite" @ Leucite Czech Republic 4.5cm |
[Metamict pseudomorphs]
The structural disintegration of minerals into a glass like state caused by alpha radiation emitted from the decay of uranium and thorium atoms in the structure of the mineral, has been known for quite some time. Such Metamict crystals have not been included in lists of pseudomorphic types until quite recently. Mitchell (Metamict Minerals, MR 4,1973, p 177), in his review noted, “These noncrystalline pseudomorphs often retain their crystal faces”. But it was Strunz (Pseudomorphosen, Der Aufschluss, 33, 1982, 319), who considered them to be a “Splinter” Group of the Paramorph. Betafite crystals often display sharp yellow-brown altered faces but the amorphous material within the interior, could not now, create those faces. Thus some believe that such crystal forms, to be a false form or a pseudomorph.
Examples
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| Zircon, Ontario, Canada 2.8cm | © Maggie Wilson |
[Kieth Harshbarger 2012]
Where did our images below come from?
These images below and those in the other Best Minerals articles on pseudomorphs were originally chosen from the Mindat's general image gallery by searching the image captions for the word "after". There were thousands to sort through and select. Then the captions were searched for the words "replaced" and "replacing". These key words turned up another horde of pseudomorphs. Then searching on the key works "altered" and "altering" added yet more. It is likely that still other pseudomorphs lurk in our database that are not included in the examples we show. If you find any of these it would be appreciated if you could bring them to our attention.
[Rock Currier 2011]
Useful notes
1. IMA approved mineral names have their first letter capitalized.
2. Group names have their first letter capitalized and are in Italic font.
3. Mixture names like limonite are all in lower case letters.
4. FOV stands for field of view or the width of the image.
5. @ is sometimes used as an abbreviation for the word after, when the caption needs to be shortened for cosmetic purposes.
6. w is sometimes used as an abbreviation for the word with, when the caption needs to be shortened for cosmetic purposes.
7. Often times there is more information about the specimen in the caption field of the full image. To see the full caption and/or to view the enlarged image of the specimen, click on the picture and it will open to a full window.
8. The symbol ~ is used in some captions to indicate an approximate size.
9. Opal and chalcedony pseudomorphs are in the article on Quartz pseudomorphs.
[Rock Currier 2011]
Acanthite is the most common silver mineral and probably occurs in every silver mine in the world. It is a black mineral, but it is a black mineral made up mostly of silver! That makes all the difference in the world in the eyes of collectors. If you don’t think that’s true, ask around and see if you can find even one collector who would rather have a good augite instead of a good acanthite. What? You don’t even have an augite in your collection? You don’t even know what augite is? That’s ok, I understand. I am not a big fan of Augites either.
In years past the black isometric looking crystals of silver sulfide were called argentite and were thought to be different in structure from the little pointy crystals of silver sulfide, thought to be orthorhombic, that were called acanthite. By the 1920s, it was becoming obvious that this was not the case. Ramsdele at the University of Michigan1 pointed out that angle measurements of argentite crystals were not those of isometric crystals and showed that the x-ray diffraction pattern of argentite and acanthite were the same. He speculated that argentite and a few other minerals of the galena group might be isometric only at high temperatures. Emmons, Stockwell & Jones2 showed that this was the case and that the inversion temperature of Acanthite was about 180° C. That left only acanthite standing as a valid species at room temperature so now curators and collectors needed to go and change the labels on all their Argentite specimens. On many specimens the label changes were not made and you will still see many specimens labeled argentite in old collections. The correct label for isometric looking crystals of silver sulfide could read Acanthite pseudomorph after argentite. Since some mineralogists don’t recognize argentite to be a valid mineral species because it does not exist at room temperature they would want to see these specimens labeled simply Acanthite. It all depends on what you definition of a mineral is. Yes, people are still arguing about that and every mineralogist worth his salt has a slightly different opinion.
Most Acanthite pseudomorphs after argentite crystals are not very shiny, but some of the newer specimens from the Rayes mine (not Reyes) are quite lustrous. I suspect that like many other sulfide minerals, after fifty or a hundred years, their surfaces will react with oxygen, ozone and other crud in the atmosphere and at least their surface chemistry will change and they will lose their luster. Crystals of about 4 cm are known but the best specimens have smaller crystals. Crystals of 2 cm are considered large. Most specimens of Acanthite are in the 5 cm and smaller range. Larger fine specimens are rare. The best specimens of this mineral are less than 18 cm in size with sharp crystals of 1.25 cm or larger. Historically, the best specimens came from Germany and Mexico. During the last twenty years the Rayes mine at Guanajuato has weighed in again with some very fine acanthites.
Fine Acanthite pseudomorphs after argentite are infrequently seen in a dealer’s stock and then perhaps as only a specimen or two. I don’t think I have ever seen a full flat of really fine acanthites except once in the inventory of Dave Bunk of Denver Colorado. Only in great museums collections are you likely to see more than one or two fine pieces. Occasionally a collector specializing in silver minerals may have several fine pieces in a drawer full of acanthite specimens, but it probably took him a lifetime to hunt them down. A fine thumbnail size acanthite specimen will probably cost you two to five hundred dollars and a good miniature or small cabinet specimen can run thousands of dollars.
Because acanthite is a black mineral it is not easily seen in dark places like smoke filled stopes; many fabulous specimens have gone unseen, ground through mills and turned into coins. Stories of miners and dealers selling fabulous acanthite specimens for a song because they were thought to be low grade galena specimens are urban legends in the collecting community. In many silver mines acanthite has been the main ore or a major ore component and many tons of fine specimen, certainly vastly more than were saved, have been lost to the smelters.
[Rock Currier, 27 December 2008]
Acanthite after Argentite
Germany
Saxony, Erzgebirge, Freiberg District
Acanthite after Argentite
Mexico
Guanajuato
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| Acanthite after Argentite 7cm wide | © Kevin Ward |
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| Acanthite @ Argentite 4cm tall | © A&M |
Acanthite after Argentite
Mexico
Guanajuato, Mun. de Guanajuato, Guanajuato, San Juan de Rayas Mine (Rayas Mine; Reyes Mine)
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| Acanthite after Argentite 3cm tall | © Rob Lavinsky |
Acanthite after Argentite
Morocco
Souss-Massa-Draâ Region, Ouarzazate Province, Djebel Saghro (Jbel Saghro), Imiter District, Imiter Mine
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| Acanthite @ Argentite 4.6cm tall | © Rob Lavinsky |
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| Acanthite after Argentite 5.3cm tall | © Rob Lavinsky |
Acanthite after Polybasite
Mexico
Guanajuato, Mun. de Guanajuato, Guanajuato
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| Acanthite after Polybasite 3.3cm wide | © Rob Lavinsky |
Acanthite after Silver
China
Anhui Province, Chaohu Prefecture, Lujiang Co.
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| Acanthite after Silver 3.3cm wide | © Jiangbin |
Acanthite after Stephanite
Mexico
Zacatecas, Mun. de Fresnillo, Fresnillo de Gonzalez Echeverria (Fresnillo)
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| Acanthite after Stephanite 2.8cm tall | © Rob Lavinsky |
Adamite after Legrandite
Mexico
Durango, Mun. de Mapimí, Mapimí, Ojuela Mine
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| Adamite after Legrandite 7.3cm wide | © RPellar |
Albite after Analcime
Norway
Akershus, Lørenskog, Feiring Bruk
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| Albite after Analcime 3.5cm tall | © AÖ 2009 |
Albite after Calcite
Norway
Vestfold, Re, Flår
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| Albite after Calcite 3cm wide | © K.E.Larsen |
Albite after Scapolite
Canada
Ontario, Renfrew Co., Greater Madawaska Township, Griffith, Khartum
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| Albite @ Scapolite 5.6 cm tall | © Rob Lavinsky |
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| Albite @ Scapolite 5cm | © Lavinsky |
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| Albite @ Scapolite 1.9cm | © Betts |
Amphabole after Aegirine
Malawi
Zomba District, Mt. Malosa
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| Amphabole @ Aegirine & Orthoclase 8.2cm tall | © Tony Peterson |
Analcime after Analcime & Siderite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
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| Analcime after Analcime 9cm wide | © 2002 John H. Betts |
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| Analcime @ Analcime 7.5cm | © Betts |
Only a handful of these unusual pseudomorphs have been found. St Hilaire has produced many very unusual pseudomorphs and you will see quite a variety of them in these articles.
Analcime after Burbankite?
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Anclcime after Cancrinite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
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| Analcime after Cancrinite 6cm tall | © D.K.Joyce |
Analcime after Laumontite
UK
Scotland, Strathclyde (Dunbartonshire), Inverclyde, Kilmacolm, Auchenbothie
Laumontite is a very unstable mineral that dehydrated rapidly when exposed to the air. Few of them last more than a few years unless great care has been taken to preserve them and even those that have often show the ravages of slow decomposition. Here we see an example of Laumontite that has been altered to Analcime.
Analcime after Laumontite
USA
Michigan, Keweenaw Co., Copper Falls
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| Analcime @ Laumontite 8.8cm wide | © Weinrich |
Analcime after Natrolite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Anatase after Perovskite and Magnetite
USA
Arkansas, Hot Spring Co., Magnet Cove, Perovskite Hill
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| An 8mm Anatase after Perovskite & Magnetite | © 2007 Peter Cristofono |
Anatase after Titanite
Canada
Ontario, Haliburton Co., Monmouth Township, Tory Hill, Bear Lake diggings (Gibson Road Western occurrence)
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| Anatase @ Titanite & Microcline 16cm | © Vonderhey |
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| close up of image to left | © Vonderhey |
Anatase after Titanite
USA
North Carolina, Henderson Co., Zirconia (Tuxedo Station), Jones Mine
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| Anatase @ Titanite 2.5cm tall | © Rob Lavinsky |
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| Anatase after Titanite 2cm tall | © |
Anatase after Titanite
USA
Texas, Llano Co., Llano, Badu Hill pegmatite
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| Anatase after Titanite 4cm tall | © 2007, F. Roberts |
Andradite after Rhodochrosite
South Africa
Northern Cape Province, Kalahari manganese fields, Hotazel, Wessels Mine (Wessel's Mine)
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| Andradite @ Rhodochrosite 5.6cm | © Lavinsky |
Anglesite after Cerussite
Australia
New South Wales, Yancowinna Co., Broken Hill
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| Anglesite after Cerussite 6cm wide | © Rob Lavinsky |
Anglesite pseudomorphs after Cerussite were quite common when these famous mines were producing, but they are not particularly attractive and that is probably why large quantities of them were not saved. Even so, you can still find them occasionally offered for sale today.
Anglesite after Cerussite
Namibia
Otjikoto (Oshikoto) Region, Tsumeb, Tsumeb Mine (Tsumcorp Mine)
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| Anglesite after Cerussite 4.3cm | © Rob Lavinsky |
Anglesite after Galena with Sulfur
Poland
Upper Silesia (Slaskie), Upper Silesian Coal Basin, Rybnik Coal Area, Rybnik, Ignacy-Hoym coal mine
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| Anglesite @ Galena w Sulfur FOV 1.7cm | © Peter Haas |
Anglesite after Galena
USA
New Mexico, Socorro Co., Hansonburg District, Bingham, Blanchard Mine (Portalas-Blanchard Mine)
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| Anglesite after Galena 4.3cm wide | © Borrelli |
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| Anglesite a. Galena 2 cm | © Betts |
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| Anglesite after Galena 5.4cm wide | © Rob Lavinsky |
Specimens of Anglesite pseudomorphs after Galena were quite common in the Blanchard and its sister mines at Bingham and you could collect them on every trip there if you wanted to. But they are not particularly attractive compared to the fluorite and other copper minerals like Brochantite, Linarite and Scorodite upon which collectors tended to concentrate. Frequently these galena crystals are only altered a bit on the outside and still retain much of the Galena in the "centers" of the crystals. But as generations of collectors and small mining have worked the deposit, good specimens from there are becoming harder to get. Perhaps at some time, if lead and copper become valuable enough the entire deposit will be open pitted and large quantities of specimens will once again be available.
Rock Currier 2011]
Anglesite after Linarite
UK
Wales, Ceredigion (Dyfed; Cardiganshire), Ceulanymaesmawr, Talybont, Nant-y-Moch Reservoir area, Eaglebrook Mine (Nant-Y-Cagel Mine; Nantycagl Mine; Nantygagal Mine; Dolrhyddlan Mine)
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| 1.5mm spray of Anglesite after Linarite | © Steve Rust |
Anhydrite after Anhydrite
Italy
Tuscany, Grosseto Province, Montieri, Campiano Mine
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| Anhydrite @ Anhydrite 10cm tall | © Marco Barsanti |
Ankerite & Albite after Aegirine & Analcime
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Ankerite after Barite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nent Valley, Nentsberry Haggs Mine
Ankerite after Calcite
France
Alsace, Haut-Rhin, Ste Marie-aux-Mines (Markirch), Neuenberg
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| Ankerite after Calcite 11cm wide | © Paul De Bondt |
It is deffinately ankerite after calcite. Many test where done on these and the more recently by Fluck and Bari in 1982 and later on. These are well known in the district for several centuries. They are part of the " paragenèse à carbonates nobles " (noble carbonates paragenesis) which is the paragenesis of the veins. The native silver and silver minerals from the district were always found near these pockets and with this paragenesis. At the museum at Ste Marie there is(was ?) a chalcopyrite crystal cluster with these doubly terminated pseudo's to 6 cm cris-cross over them. I saw that piece back in 78 and still dreaming about it.
What I find interesting about these pseudo's is that the original form of calcite ( the scalenohedron ) nearly completely dissapeared from the district except from 2 mines ( according to my observations of the specimens in many local collections and books on the district). All other calcite crystals were formed later, is of the " joplin" type or simple rhombs. The scalenohedron is observed in the Toussaint mine and in the Glück Auf (see my gallery). I saw in 1987, in a local collection, a double terminatated pseudo af ankerite after calcite on matrix sparkled with very tiny gemmy double terminated joplin calcites. Just amazing. The collection has been dispersed whem the owner passed away in that same year. I have no idea where the specimen went. It would be great to locate that piece back and take a pic of it for Mindat.
[Paul De Bondt 2011]
Annabergite after Millerite?
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nenthead, Smallcleugh Mine
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| Annabergite after Millerite FOV ~3mm | © S Rust |
Antigorite after Monticellite
Italy
Trentino-Alto Adige, Trento Province, Fassa Valley
Apatite after Wagnerite
Norway
Telemark, Bamble (Bamle), Havredal (Hafredal), Nedre Havredal, The Kjerulfine mine
Aragonite after ? with Sulfur
Italy
Sicily, Agrigento Province
Aragonite after Calcite?
Namibia
Otjikoto (Oshikoto) Region, Tsumeb
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| Aragonite @ Calcite?? 5.3cm wide | © Rob Lavinsky |
Arfvedsonite after Aegirine
Malawi
Zomba District, Mt Malosa
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| Arfvedsonite after Aegirine 3.5cm | © John Sobolewski |
Arsenogoyazite after Cuprite?
Germany
Baden-Württemberg, Black Forest, Wolfach, Oberwolfach, Rankach valley, Clara Mine
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| Arsenogoyazite @ Cuprite? FOV 3mm | © Stephan Wolfsried |
These are more likely to be after scorrodite than cuprite.
Arsenopyrite after Pyrrhotite?, Sphalerite & Calcite
Kosovo
Kosovska Mitrovica, Trepca valley, Trepca complex, Stari Trg Mine
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| Arsenopyrite @ Pyrrhotite? & etc 9cm | © Eldjarn |
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| Arsenopyrite @ Pyrrhotite? & Calcite 7cm | © Eldjarn |
Arsenopyrite after Pyrrhotite
Mexico
Chihuahua, Mun. de Aquiles Serdán, Santa Eulalia District
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| Arsenopyrite @ Pyrrhotite 9cm tall | © Rob Lavinsky |
Arsenopyrite after Pyrrhotite
Peru
Huánuco Department, Dos de Mayo Province, Huallanca District, Huanzala Mine
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| Arsenopyrite @ Pyrrhotite 8.3cm | © Lavinsky |
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| Arsenopyrite @ Pyrrhotite 6.2cm | © |
Arsenopyrite after Pyrrhotite
USA
South Dakota, Lawrence Co., Galena District, Deadwood, Double Rainbow Mine (Richmond Sitting Bull)
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| Arsenopyrite @ Pyrrhotite 3cm | © Wilson |
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| Arsenopyrite @ Pyrrhotite 10.6cm | © Rob Lavinsky |
Atacamite? after Rat
Russia
(unknown)
The specimen is in a display case in the Fersman Museum in Moscow, Russia and is labeled as Atacamite. Its not a very big rat and perhaps it might be better described as a mineralized mouse. Inquiries as to the provenence of the mouse/specimen indicates that the specimen is from an unknown locality and that it might not be after atacamite, but perhaps Chalcanthite. In fact there is speculation that the origin of the specimen might be a chemical laboratory or chemical production facility where the mouse was poisoned by the chemicals and died. I suspect that the specimen is such a big tourist attraction is the reason that it is left on display.
Augite after Monticellite
Italy
Trentino-Alto Adige, Trento Province, Fassa Valley, Monzoni Mts, Toal de la Foia
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| Augite xls to 3.7cm? @ Monticellite | © Simone Citon |
Azurite after Calcite
Greece
Attikí (Attica; Attika) Prefecture, Lavrion (Laurion; Laurium) District, Lavrion District Mines
Azurite after Chalcostibite
Morocco
Grand Casablanca Region, Casablanca Prefecture, Cherrat Wadi, Rar-el-Anz
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| Azurite after Chalcostibite 4.2cm wide | © Rob Lavinsky |
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| Azurite after Chalcostibite 8.3cm wide | © Dan Weinrich |
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| Azurite @ Chalcostibite 5.9cm | © Lavinsky |
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| Azurite after Chalcostibite 2.9cm tall | © Lavinsky |
Azurite after Cuprite
France
Rhône-Alpes, Rhône, Chessy-les-Mines
These pseudomorphs are exceptionally rare. I have only seen perhaps a half dozen of them and this was the best one to my knowledge, but certainly there must be as good or better in France somewhere. This was in the collection of Arthur Montgomery and he had three of them. He gave me his second best one and I have cherished it for many years. Arthur came to believe that possessions were a barrier that prevented spiritual progress and he eventually gave away all of his extremely fine collection to institutions and young collectors. He said "would you like some specimens? " I was so surprised I could hardly speak. He then would indicate some of the specimens you might choose from. And when I pointed to one of these pseudomorphs he said "Can you get those any more". "No Dr. Montgomery, you can't get those anymore." For every one of these azurite after cuprite, there were hundreds if not thousands of malachite pseudomorphs after cuprite produced.
[Rock Currier 2011]
Azurite after Tetrahedrite
France
Midi-Pyrénées, Ariège, Irazein
This is really an incredible specimen. It is in the collection of University of Paris (Sorbonne). Pierre Bariand, curator of the museum told me how he got the specimen for the museum. He got a call that a French school was getting rid of its collection and that he wanted any of the specimens he should come and take them. When he arrived, there was a pile of minerals/rocks on the floor and sitting on the top was this specimen. Crystals of tetrahedrite of this size are almost unheard of and the fact that this one, altered though it might be, appears to be a floater with no visible point of attachment makes it all the more amazing.
Azurite after wood
USA
Arizona, Cochise Co., Mule Mts, Warren District, Bisbee
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| Azurite after wood 5.4cm wide | © Rob Lavinsky |
Baryite after Calcite
Morocco
Meknès-Tafilalet Region, Er Rachidia Province, Taouz
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| Barite after Calcite | © M.Youssef |
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| Barite after Calcite | © M.Youssef |
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| Barite after calcite | © 1 |
Barite after Celestine
USA
Illinois, Hardin Co., Illinois - Kentucky Fluorspar District, Harris Creek Sub-District, Annabel Lee mine
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| Barite after Celestine 5.8cm wide | © Rob Lavinsky |
Baryte after Fluorite on Ferberite
Kazakhstan
Karagandy Province (Qaragandy Oblysy; Karaganda Oblast'), Betpakdala Desert (Bet-Pak-Dal Desert), Kara-Oba W deposit
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| Barite @ Fluorite on Ferberite 8.5cm | © C. Stefano '10 |
Barite after Witherite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District
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| Barite @ Witherite 8.2cm tall | © Tamás Ungvári 2005 |
Barite after Witherite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nent Valley, Nentsberry Haggs Mine
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| Barite @ Witherite 5.9cm | © Lavinsky |
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| Barite after Witherite 6.5cm tall | © Bill Dameron |
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| Barite @ Witherite ~4.5cm | © Freilich |
Barite after Witherite
UK
England, Cumbria, North and Western Region (Cumberland), North Pennines, Alston Moor District, Nenthead, Rampgill Mine
Bastnäsite-(Ce) after Petersenite-(Ce)? & Rhodochrosite
Canada
Québec, Montérégie, Rouville RCM, Mont Saint-Hilaire, Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)
Bastnäsite-(Ce) after Sazhinite-(Ce)?
Namibia
Khomas Region, Windhoek District, Windhoek, Aris, Aris Quarries (Ariskop Quarry; Railway Quarry)
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| Bastnäsite-(Ce) after Sazhinite-(Ce) | © jo-esche 2008 |
Bavenite afer Beryl
Austria
Salzburg, Hohe Tauern Mts, Obersulzbach valley
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| Bavenite after Beryl 3.3cm tall | © mslama |
Bavenite after Beryl
Norway
Aust-Agder, Evje og Hornnes, Li Quarry (Liheia)
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| Bavenite after Beryl 2.5cm | © Olav Revheim |
Bayldonite after Mimetite
Namibia
Otjikoto (Oshikoto) Region, Tsumeb, Tsumeb Mine (Tsumcorp Mine)
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| Bayldonite after Mimetite 5cm wide | © Rob Lavinsky |
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| Bayldonite @ Mimetite 3.8cm | © Rob Lavinsky |
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| Bayldonite @ Mimetite 13cm wide | © Rob Lavinsky |
Betekhtinite after Bornite
Kazakhstan
Karagandy Province (Qaragandy Oblysy; Karaganda Oblast'), Dzhezkazgan (Zhezqazghan), Dzhezkazgan Mine (Zhezqazghan Mine)
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| Betekhtinite after Bornite 4.1cm wide | © Rob Lavinsky |
Bicchulite & Hydrogrossularite after Gehlenite
Japan
Honshu Island, Chugoku Region, Okayama Prefecture, Takahashi, Bitchu-cho (Bicchu-cho), Fuka mine
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| Bicchulite @ Gehlenite 8.5cm | © Rob Lavinsky |
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| 4mm xls of Bicchulite after Gehlenite | © Rob Lavinsky |
Birnessite/Ranciéite after Serandite
Canada
Québec, Montérégie, Lajemmerais RCM, Varennes & St-Amable, Saint-Amable sill, Demix-Varennes quarry
Bismoclite after Bismuthinite, Quartz & Clinochlore
UK
England, Cornwall, Mount's Bay District, St Hilary, Croft Gothal Mine
Bismutite after Bismuthinite
USA
New Mexico, Hidalgo Co., Apache No. 2 District, Anderson-Apache mine
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| Bismutite after Bismuthinite | © 2008 Peter Cristofono |
Bornite after Chalcocite on Quartz
UK
England, Cornwall, St Just District, St Just, Trewellard, Levant Mine
Bornite after Chalcocite
USA
Wisconsin, Rusk Co., Ladysmith, Flambeau Mine
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| Bornite @ Chalcocite 3.6cm wide | © Dan Weinrich Minerals |
Brochantite after Langite
Austria
Salzburg, Hohe Tauern Mts, Kaprun valley, Kaprun, Lechnerberg Mt. (slag locality)
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| Brochantite @ Langite FOV 3mm | © Schreiber Fritz |
Brockite after Microlite
USA
Virginia, Amelia Co., Winterham, Morefield Mine (Morefield Pegmatite)
Bulfonteinite after Apophyllite on Calcite
South Africa
Northern Cape Province, Kalahari manganese fields, Kuruman, N'Chwaning Mines, N'Chwaning II Mine
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| Bulfonteinite @ Apophyllite 3.4cm | © Fabre |
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| Bulfonteinite @ Apophyllite 4.7cm | © Fabre |
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| Bulfonteinite @ Apophyllite 4.2cm | © Fabre |
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| Bulfonteinite @ Apophyllite on Calcite 2cm wide | © Fabre |
Click here to view Pseudomorphs & Replacements C. Click here to view Pseudomorphs & Replacements D to I. Click Here to view Pseudomorphs & Replacements J to M. Click here to view Pseudomorphs & Replacements N to P. Click here to view Pseudomorphs & Replacements Quartz. Click here to view Pseudomorphs & Replacements R to Z. Click here to view Best Minerals P, click here to view and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
Images last selected December 2010 sorting on: after, altered, altering, replaced & replacing
Rock Currier
Crystals not pistols.
Edited 107 time(s). Last edit at 11/25/2012 03:03AM by Rock Currier.
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Re: Pseudomorphs A December 14, 2010 07:13PM |
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Hi, Rock,
I will start the Psuedomorphs A off for you. Here is a photo of Adamite after Legrandite from the Ojuela Mine, Mapimi, Durango, Mexico. It is 7.3 x 5.5 x 2.9 cm.
I will start the Psuedomorphs A off for you. Here is a photo of Adamite after Legrandite from the Ojuela Mine, Mapimi, Durango, Mexico. It is 7.3 x 5.5 x 2.9 cm.
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Re: Pseudomorphs A December 15, 2010 01:42AM |
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Re: Pseudomorphs A December 15, 2010 11:20PM |
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Re: Pseudomorphs A December 16, 2010 04:09AM |
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Re: Pseudomorphs A December 16, 2010 07:29PM |
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Re: Pseudomorphs A December 16, 2010 09:08PM |
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Re: Pseudomorphs A to C December 26, 2010 05:54AM |
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Re: Pseudomorphs A to C December 27, 2010 05:15PM |
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Re: Pseudomorphs A to C December 27, 2010 07:34PM |
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Re: Pseudomorphs A to C December 28, 2010 02:01PM |
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Re: Pseudomorphs A to C December 28, 2010 02:17PM |
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Re: Pseudomorphs A to C December 28, 2010 08:21PM |
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Re: Pseudomorphs A to C January 01, 2011 03:44PM |
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Re: Pseudomorphs A to C January 01, 2011 05:20PM |
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Re: Pseudomorphs A to C January 01, 2011 05:44PM |
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Re: Pseudomorphs A to C January 01, 2011 06:02PM |
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Re: Pseudomorphs A to C January 01, 2011 09:47PM |
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Re: Pseudomorphs A January 04, 2011 12:29PM |
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Re: Pseudomorphs A to C January 06, 2011 10:35AM |
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Updated Mineral Entry: Schlüterite-(Y) From Uwe Kolitsch, 23rd May 2013 07:31:28