http://www.mindat.org/msgboard-82.html Sat, 28 Nov 2009 19:56:31 +0000 Phorum 5.2.8-RC1 http://www.mindat.org/forum.php?read,82,143657,143657#msg-143657 http://www.mindat.org/forum.php?read,82,143657,143657#msg-143657


Probertite
NaCaB₅O₇(OH)₄·3H₂O monoclinic

1.Probertite xl, 4.7cm tall, Kohnstein Quarry, Nordhausen, Harz Mts, Thuringia, Germany	© Thomas Witzke

At most localities, Probertite occurs as prismatic crystals that commonly are found in intergrowen radiating bundles in massive ore and only rarely exhibit well defined crystal faces. It has been found at fewer than 20 localities but at some of these localities it is abundant and in the borates ores at these localities represents hundreds if not thousands of tons of the mineral. However at the Kohnstein Quarry in Germany, they are found as well formed transparent crystals, some of which you could cut transparent faceted stones from (God forbid!). This German locality would have to be rated as producing the best crystals by one or two orders of magnitude.


Probertite
Germany
Thuringia, Harz Mts, Nordhausen, Niedersachswerfen, Kohnstein Quarry

2.Probertite xl. FOV 4.5cm	© Elmar Lackner

Free standing Probertite crystals were only found once in the Kohnstein Quarry in a series of small pockets in massive Anhydrite. This was in 1996/97. They occurred as white, clear terminated prismatic crystals up to about 10 cm in length but the larger crystals were laying flat on the matrix but the best crystals were smaller up to about 4.8cm. It was impossible to get free standing crystals on matrix due to the massive, hard nature of the anhydrite rock. Only a few terminated crystals were found and perhaps the best terminated crystal measured 4.8cm and can be seen above in Picture #1. Less than 20 good probertite crystals of more than 2 cm were found, plus 2 handful material of smaller crystals, crystals without termination and fragmented crystals (due to the very good cleavage parallel to the elongation), plus 5 - 6 flats of samples with flat laying crystals on matrix. Fibrous or radiating probertite, known from other borate deposits, were not found. A few other well crystallized borates were also found at this locality, perhaps most notably Priceite and Hydroboracite. Usually the clefts and veins that are borate rich produce only one borate mineral. Hydroboracite was much more common, and was found more or less continuously over several years. All the other borate minerals are very rare and only a few samples were found, e.g. from tuzlaite only one sample on matrix and some small loose crystals are known.


The Kohnstein Quarry, Niedersachswerfen, is an anhydrite quarry mined several years for anhydrite and now inactive.
In the active time, in the anhydrite sometimes borate minerals were found in clefts, small veins and lenses. The main borate minerals is hydroboracite.
[Thomas Witzke 2009]



Probertite
Turkey
Marmara Region, Balikesir Province, Bigadiç, Bigadiç Mine

3.Probertite, FOV 2cm	© GiovanniFraccaro

4.Probertite, FOV 2cm	© GiovanniFraccaro

5.Probertite, 3.7cm wide	© Arliguie M

We need someone to tell us about Turkish Probertite specimens.



Probertite
USA
California, Kern Co., Kramer District, Boron, U.S. Borax Open Pit Mine

6.Probertite, 4.5cm tall	© Peter Haas

There were some other flavors of Probertite specimens that were found at Boron and eventually we should have some of them pictured here, but compared to the German crystals they are nothing to write home about. Most of the specimens, and there were tons of them mined, are radiating star like masses found low in the deposit below the borax. Perhaps the best of them did not look any better than the one above in picture #6. They are certainly will not cause any collector to loose any sleep if he/she does not have an example of it in their collection.


Probertite
USA
California, Los Angeles Co., Lang, Tick Canyon, Lang Mine (Sterling Mine; Tick Canyon Borax Mine)

7.Probertite, FOV 6.5cm	© Rui Nunes 2007

The Probertite specimens from Tick Canyon have been available to local collectors from Los Angeles for years and undoubtedly several tons of them have been hauled away and placed in collection drawers, boxes in garages and in flower gardens. Most of the stuff that has been hauled out of the borate locality at Tick Canyon has been nodules of Howlite that had some small desirability and value for lapidary purposes. The Probertite specimens from this locality are not much in demand and most of them that were collected there were probably mistaken for Howlite nodules. The one shown in picture #7 is a good example of a typical specimen. They get larger, but not better and for that matter not much worse either.]]> Rock Currier Best Minerals P Thu, 02 Jul 2009 20:40:32 +0000 http://www.mindat.org/forum.php?read,82,140836,140836#msg-140836 http://www.mindat.org/forum.php?read,82,140836,140836#msg-140836


Prehnite
Ca₂Al₂Si₃O₁₂(OH) Orthorhombic

Prehnite Crystal, doubly terminated ~4cm Asbestos, Quebec, Canada	©

Usually prehnite is found as a botryoidal bubbly green mineral and there are plenty of examples of this kind of prehnite below. Sometimes however it is found in fine sharp crystals, but those are not common and are probably best exampled by specimens from Asbestos, Quebec, Canada like the one pictured above. Most collectors unless they have seen some of these relatively rare crystals would not even be able to identify them as prehnite. So what are the best prehnite specimens? I am partial to the wonderful crystals from Asbestos, Quebec, but then when I see some of the great prehnite snake head casts from Lower New Street quarry I think, well perhaps those are the best. Then there are the amazing balls of orange crystals from the Manganese mines near Kuruman in South Africa and then some of the fine combinations of Prehnite and Epidote crystals from the recent find in Mali are pretty amazing as well. I guess Ill just have to get some of all of those. Fine examples of these and many more you can see below. I wish I had them all. Remember the mantra of all good collectors! "Everything is not nearly enough."

Prehnite, when it is found is often plentiful, especially in basalts and is frequently found with other “zeolite” type minerals. One old time collector in New Jersey told me that on a good day he could drive his pickup (truck) into the Park (Prospect Park Quarry (Sowerbutt Quarry; Vandermade Quarry; Warren Brothers Quarry) and fill it up with prehnite specimens that lay scattered about in the blast pile. I have collected in this quarry on a good day and you could look around the quarry (you looked only in the upper most walls because the lower basalts were almost always barren) and I could count ten or twenty open pockets. Only the occasional pocket had great specimen in it but when each blast produced that many pockets you know that wonderful things were produced from time to time.

Other localities, like the alpine vein kind of localities often produce fine prehnite specimens, but they are very stingy compared to the basalt localities. However many basalts don’t have any prehnite to speak of at all. Like most of the zeolitic basalt locations in India or in northern Uruguay or southern Brazil. Almost all the prehnite specimens produced in the Deccan basalts is found near Bombay, almost exclusively at the quarry known as Malad. The Uruguayan and Brazilian basalts, though famous for their abundant amethyst specimens have few other associated minerals occurring in their amygdaloidal cavities. Sometimes skarn deposits produce abundant prehnite specimens. Most notably are the specimens from the Kays region of Mali that has produced literally tons of prehnite. Most of this prehnite has been sent in containers to the lapidary factories in China for conversion into beads and carvings. Ultimately much of it probably gets sold off as “jade” to unsuspecting customers who have never heard of Prehnite, but have heard of Jade.

Prehnite is also a very tough mineral and will even survive pretty much intact in a blast pile. When I got my first shipments of prehnite specimens from Mali, they were not individually wrapped but rather thrown all jumbled together in big burlap bags. I thought most of them would be ruined beyond redemption by this rough treatment and watched with dismay as the first bag full was dumped onto the cleaning screens. To my amazement, after pressure washing and cleaning with an air abrasive tool using glass beads (hardness of about 5.5) the prehnite looked almost untouched and it was rare to find one that appeared to be damaged. You almost have to hit one directly with a hammer to cause it much damage. If you so much as look at some minerals like barite, they seem to break, but prehnite is a tough customer. Who says you can’t teach an old dog new tricks.

Prehnite is a mineral that has been known for a long time. It was named after Colonel Hendrick von Phren (1733-1785) who discovered the mineral near the Cape of Good Hope in South Africa. I am not sure if anyone even knows where this locality is today or if the type material was ever saved. It has other names other than Prehnite. Sage called it chrysotile and Rome' de Lisle assigned it to the schorl group in 1783. Werner gave it the name Prehnite in 1790 and that name has stuck with us so far. Because of the almost universal twinning of Prehnite, the crystal structure of the mineral was not resolved till 1990 on Prehnite from Komiža, Vis Island, Split-Dalmatia County, Croatia. The Handbook of Mineralogy says the largest crystals are 4 cm, but I have seen large ones from Asbestos, Quebec though they are not all that sharp.
1.Crystal structure of prehnite: Zunic, T.B., S. Scavnicar, and G. Molin (1990 Crystal structure of prehnite from Komiza. Eur. J. Mineral., 2, 731-734.
[Rock Currier 2009]



Prehnite
Australia
New South Wales, Cumberland Co., Prospect (Prospect Hill), Prospect Quarry

Prehnite ~10cm wide	©

Prehnite ~6cm wide	©

Prehnite & Analcime ~7cm wide	©

Prehnite & Quartz, 2.2cm tall	© Earthstones

The quarry has produced specimens over a long period of time and large specimens are not uncommon. I have heard Australian collectors comment that it was hard to get good small ones.


Prehnite
Australia
New South Wales, Gowen Co., Coonabarabran

Prehnite, 12.3cm wide	© finestminerals.com

We need someone to tell us about the prehnite specimens from this locality.


Prehnite
Australia
Gunnedah, Pottinger Co., New South Wales

Prehnite, 7.7cm wide	© JSS

We need someone to tell us about the specimens from this locality.


Prehnite
Australia
New South Wales, Pottinger Co., Mullaley

Prehnite, 12.5cm wide	© Mark Rheinberger

Prehnite, 7.5cm wide	© Greg Andrew

Prehnite, 5.3cm wide	© JSS

Prehnite, 7.5cm tall	© Mark Rheinberger09

We need someone to tell us about the prehnite specimens from this locality.


Prehnite
Australia
Tasmania, Tasmania, Tasmania

Prehnite xls. 6mm wide	© crocoite.com

We need someone to tell us about the Prehnite specimens from this locality.


Prehnite
Austria
Carinthia, Koralpe Mts, Kamp, Fraßgraben

Prehnite, 8.5cm wide

A pretty ugly prehnite. I wonder if better are produced at this locality. We need someone to tell us about them.


Prehnite
Austria
Salzburg, Hohe Tauern Mts, Habach valley
There are a number of prehnite localities in the Habach valley that produce prehnite and among those pictured here are: Breitfuß Mt. - Großer Finagl Mt. area; Großer Finagl Mt., Gamsmutter Mt. (east slope); Kratzenberg Mt., Prehnite Island and Teufelsmühle. To know somewhat more precise localities, just click on the image of your choice and read the complete captions when the full size image appears.

Prehnite on Quartz, 8cm wide	© Gerd Stefanik

Prehnite, 6cm wide	© Gerd Stefanik

Prehnite, 13 cm wide	© Rob Lavinsky

Prehnite, 6cm wide	© Gerd Stefanik

Prehnite, 17.4cm tall	© Rob Lavinsky

We need someone to tell us about the specimens from these localities.


Prehnite
Austria
Styria, Stubalpe Mts, Hennereben, Roßbachgraben

Prehnite, 8.5cm wide	© Gerd Stefanik

We need someone to tell us about the specimens from this locality.



Prehnite
Canada
Québec, Richmond Co., Shipton Township, Asbestos, Jeffrey Mine (Jeffrey Quarry)

Prehnite xls. ~4cm wide	©

Prehnite, 4.1cm wide	©

Prehnite, ~7cm wide	©

Prehnite, 4.3cm wide	© Rob Lavinsky

Prehnite ~7cm across	©

Prehnite, 9cm wide	©

Prehnite & Vesuvianite, ~5cm tall	©

Prehnite, ~7cm tall	©

Prehnite xls. ~8cm wide	©

Prehnite, ~2.5cm wide	©

Prehnite, (stilbite look alike) ~7cm wide	©

Prehnite, ~7cm wide	©

Prehnite, ~7cm across	©

The big open pit asbestos mine at Asbestos, Quebec on occasions gobbled up bits of the town as they either slid into it or had to be moved to accommodate mining. Eventually, health concerns related to the use of asbestos caused a great decline in demand for asbestos and the mine to became unprofitable. It is now closed. But during its operation, the mine produced some of the finest specimens of grossular garnets thus far found. In addition, but well less known, were world class specimens of Prehnite, Vesuvianite, Pectolite and other minerals. In the case of Prehnite I believe Asbestos has produced the best examples of crystallized prehnite in the world. The Hnadbook of Mineralogy, Anthony et. al. sites the largest Prehnite crystal as being 4 cm but I saw one crystal, from the same pocket as the one at the lower left above that measured 10 cm and I doubt that I saw the largest. The sharp, steep pyramidal crystals shown above an the one at the lead in of this article may be the finest prehnite crystal found to date. I used to have fun running sight identification contests where I would show five or six substantially different, but well crystallized examples of Prehnite from Asbestos and no one would ever guess what they were let alone where they were from. Then I would sit back and enjoy the groans when my victims found out that they were all prehnite specimens from Asbestos. There was one good size pocket, perhaps the size of a bushel basket that produced most of the well crystallized prehnites with steep bipyramids with pointed tips. Perhaps three or four flats of material in all. They were collected by the mine geologist, Francisco Spertini and though not colorful, I think they were the best specimens of crystallized prehnite found to date.
[Rock Currier 2009]


Prehnite
China

Prehnite, ~8cm in diameter	©

This giant ball of stilbite is in the British Museum of Natural history. When I first saw it I didn't believe it was real, but it is. The only locality the keeper of minerals had was that it was from China. I hope by including it here that someday someone will be able to tell me where it is from exactly.


Prehnite
China
Sichuan Province, Liangshan Autonomous Prefecture, Meigu Co., Ganzhizhou Mine

Prehnite & Quartz 4.3cm wide	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
China
Sichuan Province, Liangshan Autonomous Prefecture, Meigu Co., Hongquizhen Quarry

Prehnite & Quartz, 4cm wide	© JSS

Prehnite & Quartz, 7.2cm wide	© JSS

Prehnite, 4.6cm wide	© Safaa Yu

Prehnite & Quartz, 5.4cm wide	© Rob Lavinsky

Prehnite & Quartz, 7.4cm wide	© Rob Lavinsky

Prehnite & Chrysocolla, 5.4cm	© Rob Lavinsky

Prehnite, Epidite & Quartz, 5.9cm wide	© Rob Lavinsky

We need someone to tell us abut the specimens from this locality.


Prehnite
China
Yunnan Province, Zhaotong Prefecture, Qiaojia, Qiaojia Co.

Prehnite & Quartz, 10cm wide	© Rob Lavinsky

Prehnite, Quartz & Babingtonite 4.5cm	© Jiangbin

Prehnite & Quartz, 5.5cm	© Jiangbin

We need someone to tell us about the specimens from this locality. There appear to be at least too good localities for prehnite in China and I know at least one of them produces abundantly. I have been offered two or three lots of them and each lot had several hundred specimens of Prehnite/Quartz combinations.


Prehnite
France
Rhône-Alpes, Isère, Bourg d'Oisans

Prehnite, 8cm tall	© Paul De Bondt

Prehnite, ~8cm wide	©

Prehnite, ~6cm tall	©

Prehnite, 6.4cm wide	© Paul De Bondt

We need someone to tell us about the specimens from this locality.


Prehnite
Germany
Lower Saxony, Harz Mts, Bad Harzburg

Prehnite, ~9cm wide	©

We need someone to tell us about this locality and its specimens.


Prehnite
Germany
Lower Saxony, Harz Mts, St Andreasberg District, St Andreasberg

Prehnite, 7cm wide	© 2002 John H. Betts

We need someone to tell us about this locality and its specimens.


Prehnite
Germany
Rhineland-Palatinate, Niederkirchen, Rauschermühle Quarry

Prehnite, 9.5cm wide	© Rob Lavinsky

Prehnite, 5cm wide	© Volker Betz

We need someone to tell us about this locality and its specimens.


Prehnite
Germany
Rhineland-Palatinate, Wolfstein, Kreimbach-Kaulbach, Andesite quarry

Prehnite, 2.8cm wide	©

We need someone to tell us about this locality and its specimens.


Prehnite
Germany
Saxony-Anhalt, Harz Mts, Wernigerode, Schierke, Wormke bend

Prehnite, 9cm wide	© 2001 John H. Betts

We need someone to tell us about this locality and its specimens.


Prehnite
India
Maharashtra, Bombay, Ward 38, Malad

Prehnite after Laumontite, 4.5cm wide	© 2001 John H. Betts

Prehnite & Gyrolite ~5cm wide	©

Prehnite & Laumontite ~4cm tall	©

Prehnite & Gyrolite ~10cm tall	© Tony Peterson

Prehnite after Laumontite, 9.4cm wide	© Rob Lavinsky

Prehnite after Laumontite 11cm wide	© G. van der Veldt

Prehnite is a rare mineral in the Deccan trap rocks of India except at Malad where is is common as pale, almost white little hemispheres growing on quartz and other minerals in the amygdaloids (pockets) of it's pillow basalts. The small blebs of prehnite can be mistaken for small balls of Gyrolite but if you look carefully at them they have a greater degree of translucency and often a very pale green color where as the balls of Gyrolite are more opaque. It is a rare prehnite specimen from Malad that has a good green color. It is not uncommon to find pale green prehnite "sticks" of prehnite, usually growing in clusters that are casts after prismatic laumontite. I have a few specimens in my collection where the laumontite is still intact inside these casts. Initially they were thought to be casts after anhydrite like the casts after anhydrite that are common in the quarries of the Watchung basalts in New Jersey. Most of the amygaloidal cavities that produced the specimens for which the quarry is well known are smaller than a wash tub, but back in the late 60s a large walk in pocket lined with prehnite casts was found. It was large enough that you could almost stand upright in it. Many of the cast clusters were coated with a black material that was later found to be a very pure form of Todorokite which I found much to my delight could be easily removed with a slightly acidified solution of hydrogen peroxide. Also much to my profit, because the dirty black cast clusters were purchased for very little money. Some times these casts had other minerals growing on them, most commonly blocky crystals of Apophyllite-(KOH). Malad has probably produced the worlds best speicmens of this variety of apophyllite as well as the best specimens of Okenite, Gyrolite and Yugawaralite. The specimens from Malad are almost always found growing on small drusy white quartz crystals that commonly line the pockets and the assemblage is distinctive enough that once you are familiar with it, you can always spot a specimen from Malad.

The quarries are located not far from the main north/south railway line that connects Bombay to the mainland. They are located just three kilometers east of the town of Malad and its railway station. You can see them easily from satellite images. In the 60s this part of northern Bombay was almost rural and those who dealt in specimens from there would get off the train at the Malad station and walk or take what ever transport they could command and travel to the quarries. If however you had a car you would most likely travel to the next little town Khandivili (Kandivili) and then back track a little to get to the quarries because there was no road directly from Malad to the quarries. For this reason the name Kandivili or Khandivili became attached to the quarries. They were also by some dealers called the Bombay quarry. There were seven quarries and they were numbered from south to north. When facing the quarries looking east, the number one quarry was the furtherest one south or to your right. The number 2 quarry was where almost all of the Yugawaralite specimens came from. Over the years, the quarries more or less worked into each other and so the quarry numbers are not very meaningful. Today the quarries are not active and it is an area of slum housing.
[Rock Currier 2009]


Prehnite
Italy
Aosta Valley, Champdepraz, Monte Barbeston

Prehnite, 13 cm wide	© Marco Macchieraldo

We need someone to tell us about the specimens from this locality.


Prehnite
Italy
Piedmont, Torino Province, Sesia-Lanzo zone, Lanzo Valley, Viù Valley, Usseglio, Margone

Prehnite, 2.1cm wide	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
Italy
Trentino-Alto Adige, Trento Province, Fassa Valley, Duron Valley, Col Rodella

Prehnite, ~2.5cm wide	© Chinellato Matteo

We need someone to tell us about the specimens from this locality.


Prehnite
Italy
Veneto, Vicenza Province, Recoaro Terme, Civillina Mt.

Prehnite & Rhodochrosite ~13cm wide	© Gianfranco Capolupi

We need someone to tell us about the specimens from this locality.


Prehnite
Kazakhstan
Zhezqazghan Oblysy (Dzezkazgan Oblast'; Dzhezkazgan Oblast'; Djezkazgan Oblast'; Jezkazgan Oblast')

Prehnite	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
Mali
Kayes Region, Bafoulabé Circle, Djouga

Prehnite, 15.5cm high	©

Prehnite on Epidote 608cm tall	©

Prehnite cast, 13.4cm tall	©

Prehnite balls 2 to 2.7cm	©

The prehnite, epidote and garnet specimens from Mali all derived from the discovery of green grossular garnets in the Kays region of Mali back in 1994, It was reported in the newspapers that emeralds had been discovered. There was a gem rush of sorts that in a small way resembled the early gold rushes in California and other places and at one time there were several thousands of locals digging for these emeralds. It was soon discovered that they were garnets and not emeralds, but it got a lot of people digging for stuff. Soon these diggers started looking at other near by skarn deposits that conveniently outcropped on the sides of many hills in the region and in addition to garnets of various colors they found prehnite and epidote specimens. Perhaps the best and most prolific of the prehnite localities were the hillside diggings about five kilometers north of Bendoukou village in the Kays region of Mali. Local diggers started producing tons of Prehnite which sometimes contained a good portion of nice specimen material. This material was taken to Bamako, the capitol of Mali and from there sold to whoever would pay the best price. Most of the material was put in containers and sent to China as fodder for their big Lapidary factories to be turned into beads and small carvings of various kinds. Over several years we bought several thousand pounds of prehnite, garnet and epidote specimens and the best of them were really spectacular. Especially desirable were the combination pieces of black epidote crystals with balls of green prehnite growing on them. Many of the prehnite specimens were in the form of complete balls of Prehnite or several of these balls that had grown together. As time passed other localities for prehnite and garnets were found in the various skarns of the region and I am sure as more time passes, there will be more localities that will each produce a somewhat different flavors of prehnite, garnets, epidotes and other related minerals.


Prehnite
Mali
Kayes Region, Nioro du Sahel Circle, Sandaré

Prehnite	© Rob Lavinsky

Prehnite, 3.1 cm wide	© Rob Lavinsky

These specimens were produced from a locality similar to the one described above.


Prehnite
Morocco
Meknès-Tafilalet Region, Er Rachidia Province, High Atlas Mts, Imilchil

Prehnite, ~3cm wide	© Elmar Lackner

Prehnite, 10cm wide	© Rob Lavinsky

Prehnite, 6.3cm wide	© Safaa Yu

Prehnite on Orthoclase 4cm wide	© Martins da Pedra

Prehnite, 5.2cm tall	© Rob Lavinsky

Prehnite & Quartz, 4.5cm wide	© Rob Lavinsky

We need someone to tell us about the specimens produced at this locality.


Prehnite
Morocco
Oriental Region, Figuig Province, Bou Arfa, Djebel Melh

Prehnite, 6.8cm tall	© fabreminerals.com

Prehnite, 9cm wide	© fabreminerals.com

We need someone to tell us about the specimens produced by this locality.


Prehnite
Morocco
Taza-Al Hoceïma-Taounate Region, Taza, Taza Province

Prehnite 5cm wide	© Martins da Pedra

Prehnite ~8cm	© Martins da Pedra

Prehnite, 7.5cm wide	© Thomas Witzke

We need someone to tell us about the specimens produced at this locality.



Prehnite
Namibia
Erongo Region, Brandberg District, Brandberg area

Prehnite & Quartz, 5.8cm	© Rob Lavinsky

Prehnite on Quartz, 2.7cm tall	© Rob Lavinsky

Prehnite & Quartz, 6.1cm tall	© Rob Lavinsky

Prehnite on Quartz, 3.0cm tall	© Rob Lavinsky

Prehnite, 4cm wide	© Rob Lavinsky

Prehnite & Quartz, 7.9cm wide	© Rob Lavinsky

I think Charles Key got many of the good prehnite specimens from this locality that have made their way to the USA.
[Rock Currier 2009]


Prehnite
Namibia
Erongo Region, Brandberg District, Brandberg area, Goboboseb Mountains

Prehnite on amethyst xl, 6.6cm tall	© Rob Lavinsky

Prehnite on Quartz xl. 3.2cm tall	© Rob Lavinsky

Prehnite, 5cm wide	© 2001 John H. Betts

Prehnite on amethyst xl. 5cm tall	© michael berghäuser

Prehnite, 4cm long	© 2001 John H. Betts

Prehnite & Quartz, 6 cm tall	© michael berghäuser

Prehnite & Calcite, 6cm wide	© 2001 John H. Betts

Prehnite & Calcite, 9cm wide	© Edelmin

I think Charles Key was responsible for many of the fine prehnite specimens that have found their way into the US market. They were never abundant, and the good ones quite rare.


Prehnite
Norway
Aust-Agder, Risør, Søndeled

Prehnite, 4cm wide	© Jorge M. Alves

We need someone to tell us about the specimens from this locality.


Prehnite
Norway
Aust-Agder, Risør, Søndeled, Ravneberget quarry

Prehnite, 15cm wide	© Knut Eldjarn

We need someone to tell us about the specimens from this locality.


Prehnite
Norway
Buskerud, Kongsberg

Prehnite & Calcite, ~8cm wide	©

We need someone to tell us about the specimens from this locality.


Prehnite
Pakistan
Balochistan (Baluchistan)

Prehnite & Quartz, 8.4cm wide	© Rob Lavinsky

Prehnite casts, ~13cm wide	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
Pakistan
North-West Frontier Province

Prehnite, 3.1cm wide	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
Pakistan
North-West Frontier Province, Malakand Region, Swat District (Swat Valley), Mullah Yusef

Prehnite, 7.9cm across	© H. Obodda

We need someone to tell us about the specimens from this locality.


Prehnite
Portugal
Leiria District, Monte Redondo, Leiria, Montijos Quarry

Prehnite, ~7.5cm	© Martins da Pedra

Prehnite, 4cm wide	© Martins da Pedra

We need someone to tell us about the specimens from this locality.


Prehnite
Russia
Eastern-Siberian Region, Taymyrskiy Autonomous Okrug, Taimyr Peninsula, Putoran Plateau

Prehnite, 5.5cm wide	© Oleg Lopatkin

We need someone to tell us about the specimens from this locality.


Prehnite
South Africa, Republic of
Northern Cape Province, Calvinia, Zoetwater (Soetwater)

Prehnite, 11.8 cm wide	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
South Africa, Republic of
Northern Cape Province, Kalahari manganese fields, N'Chwaning Mines

Prehnite on Xonotlite, 3.5cm tall	© Rob Lavinsky

Prehnite, 3.7cm wide	© Rob Lavinsky

Prehnite, 4.5cm wide	© Rob Lavinsky

Prehnite, 5.4cm wide	© Rob Lavinsky

Prehnite & Xonotlite, 4.7cm wide	© Rob Lavinsky

Prehnite on Calcite, 5.1cm tall	© Rob Lavinsky

Prehnite on Calcite, 5.4cm tall	© Rob Lavinsky

Prehnite, 6.3cm tall	© Rob Lavinsky

Some of these small prehnite specimens are amazing. The most striking thing about them is there orange color. I think that most of the ones that have made their way to the collectors in the USA were brought here by Charles Key who lives part of the time in Namibia. The locality is a stingy one and there were probably no more that two or three flats of this material found.


Prehnite
Spain
Andalusia, Jaén, Carchelejo, Oficarsa Quarry (Cerro de las Culebras)

Prehnite, 5cm wide	© Carlos Pareja

Prehnite ball 4cm wide	© Carlos Pareja

Prehnite, 5cm wide	© fabreminerals.com

Prehnite, 6cm tall	© E-Minerales

Prehnite, 6cm wide	© Carlos Pareja

Prehnite, 6.7cm wide	© fabreminerals.com

Prehnite, 5.7cm wide	© fabreminerals.com

The prehnites from Spain can be surprisingly good. We need someone to tell us about the specimens from this locality.


Prehnite
Spain
Andalusia, Seville, Lebrija

Prehnite, 5cm wide	© Martins da Pedra

Prehnite ~5cm wide	© Rui Nunes 2007

Prehnite ~3.5cm wide	© Rui Nunes 2007

We need someone to tell us about the specimens from this locality.


Prehnite
Switzerland
Grischun (Grisons; Graubünden)

Prehnite, 7cm tall	© 2001 John H. Betts

Prehnite ~6cm across	©

Prehnite, ~6cm across	©

We need someone to tell us about the specimens from this locality.


Prehnite
Tanzania
Arusha Region, Lelatema Mts, Merelani Hills (Mererani)

Prehnite, 2.5cm tall	© Rob Lavinsky

Prehnite 3.3cm tall	© Rob Lavinsky

Prehnite ball, 1.8cm wide	© Houran Collection

Prehnite, 3.3cm wide	© Rob Lavinsky

When these yellow prehnites were first found, they were thought to be Adamite crystals. Some have even been found growing on purple crystals of tanzanite. We need someone to tell us about the specimens from this locality.


Prehnite
United Kingdom
Scotland, Central Region (Stirlingshire), Campsie Fells

Prehnite ~7cm wide	©

We need someone to tell us about the specimens from this locality.


Prehnite
United Kingdom
Scotland, North West Highlands (Inverness-shire), Isle of Skye, Soay Sound, Sgurr nan Cearcall

Prehnite, 6cm wide	© M.Wood

We need someone to tell us about the specimens from this locality.


Prehnite
United Kingdom
Scotland, Strathclyde (Ayrshire), Beith, Loanhead Quarry

Prehnite ~15cm tall	© J.Ralph 2004

Prehnite ~3cm wide	© 2002, Gordon Derry

We need someone to tell us about the specimens from this locality.


Prehnite
United Kingdom
Wales, Pembrokeshire (Dyfed), St David's Head, Quartz vein outcrop

Prehnite ~5cm wide	© Ian Jones

We need someone to tell us about the specimens from this locality.


Prehnite
USA
Connecticut, Connecticut, East Granby, Roncari quarry (Tilcon quarry)

Prehnite cast, ~5cm wide	©

Prehnite, 9cm wide	© 2002 John H. Betts

Prehnite, ~12cm wide	©

Prehnite & Calcite, ~7cm wide	©

Prehnite & Calcite, ~7cm wide	©

Prehnite & Calcite~7cm wide	©

Prehnite & Calcite, ~3.5cm wide	©

Prehite & Datolite, ~4cm tall	©

Prehnite & Babingtonite ~2cm wide	© Paul Gilmore

Better known from this quarry are its specimens of Datolite specimens, but the quarry has produced some very fine combination specimens. I know one old ex quarry worker that has a whole basement full of specimens from this quarry that will someday come to market or be thrown out on the dump.
[Rock Currier]


Prehnite
USA
Connecticut, Litchfield Co., Woodbury, O & G Woodbury Quarry (Orenaug Quarry; O & G No. 1 Quarry)

Prehnite & Apophyllite, 8.9cm wide	© Henry Minot 2008

Prehnite on Calcite, 4.1cm wide	© Henry Minot 2008

We need someone to tell us about the specimens from this locality.


Prehnite
USA
Connecticut, New Haven Co., Southbury, O & G Southbury Quarry (Silliman Quarry; O & G No. 2 Quarry)

Prehnite, 10.4cm wide	© Rob Lavinsky

Prehnite, 5.9cm wide	© 2001 John H. Betts

Prehnite, 25cm wide	© 2008 Peter Cristofono

Prehnite, 4cm tall	© Martins da Pedra

Prehnite & Quartz, 4cm wide	© Martins da Pedra

We need someone to tell us about the specimens from this locality.


Prehnite
USA
Maine, Knox Co., Thomaston, Old Country Road locality

Prehnite xls. 4cm tall	© 2002 John H. Betts

We need someone to tell us about the specimens from this locality.


Prehnite
USA
Maine, Washington Co., Calais

Prehnite xls. ~7cm wide	©

We need someone to tell us about the specimens from this locality.


Prehnite
USA
Massachusetts, Northfield, Franklin Co., Lane's Quarry

Prehnite stalactites 5cm tall	© Rob Lavinsky

Prehnite, 7cm wide	© 2001 John H. Betts

Prehnite & Datolite, 8cm wide	© Rob Lavinsky

Prehnite, 7cm across	© 2001 John H. Betts

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Hampshire, Merrimack Co., Warner, Prehnite locality

Prehnite, 2.5cm across	© 2001 John H. Betts

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Bergen Co., Fort Lee

Prehnite, ~4cm wide	©

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Essex Co., Livingston, Riker Hill

Prehnite & limonite, 8.5cm tall	© 2007 FAI III

Prehnite, 4.4cm wide	© 2007 FAI III

Prehnite, ~7cm across	©

Prehnite, ~9cm across	© EAS 2008

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Passaic Co., Haledon, Braen Quarry (Braen Stone Industry Quarry; Sam Braen Quarry)

Prehnite on matrix, 4cm wide	© 2007 FAI III

Prehnite, ~11cm wide	© EAS 2008

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Passaic Co., Little Falls Township, Great Notch

Prehnite on Calcite, ~8cm wide	©

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Passaic Co., Paterson, Hoxie's Quarry

Prehnite, ~12cm across	©

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Passaic Co., Paterson, Lower New Street quarry

Prehnite snake head, ~8cm wide	©

Prehnite after Anhydrite ~18cm wide	©

Prehnite snake heads, ~8cm wide	©

Prehnite, 9.5cm wide	© 2007 FAI III

Prehnite stalactites ~7cm tall	©

Prehnite snake heads ~5cm tall	©

Prehnite snake head ~3cm tall	©

Prehnite after Anhydrite ~7cm wide	©

Prehnite snake heads ~10cm wide	©

Lower New Street quarry is one of the old time localities that has been abandoned for years and though plans to build on the site were made, the quarry is still there and local collectors manage to find a few things from time to time. Lower New Street is the quarry that produced the best examples of the so called Prehnite snake head casts after anhydrite that collectors of New Jersey trap rock minerals revere. Ernest Weidhaas of Mt. Vernon New York seemed to have the lions share of the best ones I saw and some of the best are pictures above including the great one that he paid the equivalent price of a new care back in the 50s.

Notice that some of the Prehnite snake head casts and some of the other prehnite specimens look dirty. They have little speckles of stuff on them. You may also notice that many of my other pictures (the ones with the little one inch brass scale bar at the bottom) look dirty. On some of them you can actually see dirt down in the cracks of the specimens. That is because there were taken of old time specimens in old collections. More than about 20 years ago, collectors, dealers and curators did not have the wonderful little high pressure "fabric" guns that shoot streams of high pressure water that are commonly used today to clean up specimens and are so adroit at ferreting dirt out of every little crack. About the best they had back then were little brushes of various kinds that were really not very good at cleaning up specimens. I took these pictures mostly in museums and old collections, and it was not practical to clean them or often polite to suggest that their specimens were dirty and needed cleaning. Many of todays dealers make a lot of money by doing nothing more than blasting the dirt off of old specimens.
[Rock Currier 2009]


Prehnite
USA
New Jersey, Passaic Co., Paterson, Upper New Street Quarry (Burger's Quarry)

Prehnite casts, 10cm wide	© 2007 FAI III

Prehnite casts, 9cm wide	© 2007 FAI III

Prehnite, 20cm wide	© EAS 2007

Prehnite, 6.7cm wide	© Rob Lavinsky

Prehnite & Calcite, 10.2cm wide	© 2007 FAI III

Prehnite "finger", 6.5cm tall	© Rob Lavinsky

We need someone to tell us about the specimens from this locality.


Prehnite
USA
New Jersey, Passaic Co., Prospect Park, Prospect Park Quarry (Sowerbutt Quarry; Vandermade Quarry; Warren Brothers Quarry)

Prehnite cast ~6cm tall	©

Prehnite after glauberite ~10cm wide	©

Prehnite on Calcite, 7.9cm wide	© 2007 FAI III

Prehnite fingers 11.3cm wide	© 2008 FAI III

Prehnite 6.4cm wide	© 2002 John H. Betts

Prehnite, 10.4cm wide	© 2007 FAI III

Prehnite ~23cm wide	© EAS 2007

Prehnite & minor Laumontite ~12cm wide	© EAS 2008

©

Prehnite & Calcite ~15cm wide	©

Prehnite cast, ~6cm wide	©

This locality is probably the best known of all the New Jersey trap rock quarries. It has been producing specimens for more than 75 years but will probably close down in the next five or ten years. Only the upper level in the quarry has produced good specimens and the lower levels and the underlying sandstone has been encountered on the lowest level. The quarry has produced many tons of prehnite specimens as well as fine Datolites, Analcime, Pectolites, Thompsonites as well as good Calcites, Natrolites and others. It has even produced at least one amazing small wire silver specimen. This quarry and others in the region have attracted many field collectors and many of these collectors have gone on to become well known dealers, curators and authors. George Kunz, John Sinkankas, Charles Key, and Richard Kosnar are just a few of the hoard of the better known people that the trap rock quarries have produced.

Often the prehnite specimens from this quarry show signs of being casts after anhydrite and glauberite that were apparently at one time common in the amygdaloids of the Watchung trap rocks and crystallized before the "zeolite" minerals. The anhydrite casts are rectangular in cross section, often very flat rectangles and often look like knife slashes on the backs of the Prehintie specimens. The glauberite casts are less often seen and their casts are often diamond shaped. Both kinds can be seen in specimens from this and other quarries.


Prehnite
USA
New Jersey, Passaic Co., West Paterson, Pumping Station, McBride Ave. & Browertown Rd.

Prehnite, 6.8cm wide	© 2008 FAI III

Prehnite & Calcite, 12cm wide	© 2008 FAI III

Prehnite fingers, 5.3cm wide	© 2008 FAI III

Prehnite, 8cm wide	© 2008 FAI III

Prehnite & Calcite 10cm wide	©

We need someone to tell us about the specimens from this quarry.


Prehnite
USA
New Jersey, Passaic Co., West Paterson, Union Building and Construction Quarry (UBC Quarry; Tilcon Quarry)

Prehnite, Prehnite fingers, 5.5cm wide	© 2009 FAI III

We need someone to tell us about the specimens from this quarry.


Prehnite
USA
New Jersey, Somerset Co., Bernards Township, Millington Quarry (Morris County Crushed Stone Co. Quarry; Tilcon Quarry)

Prehnite 4.4cm wide	© 2007 FAI III

Prehnite on matrix, 9.5cm wide	© 2007 FAI III

Prehnite on Datolite, 7cm wide	© 2007 FAI III

Prehnite & Natrolite, 5cm wide	© EAS 2008

We need someone to tell us about the specimens from this quarry.


Prehnite
USA
New Jersey, Somerset Co., Bridgewater Township, Chimney Rock Quarry (Houdaille Industries Quarry; The Bound Brook Quarry; Stavola Industries Quarry)

Prehnite, 12cm wide	© EAS 2008

We need someone to tell us about the specimens from this quarry.


Prehnite
USA
New Jersey, Somerset Co., Watchung, Fanwood Crushed Stone Co. Quarry; Scotch Plains Quarry; Weldon Quarry)

Prehnite after glauberite, 14.3cm wide	© 2007 FAI III

Prehnite after glauberite, 10.3cm wide	© 2007 FAI III

Prehnite after glauberite 8.9cm wide	© Rob Lavinsky

Prehnite & Calcite 12.5cm wide	© 2007 FAI III

Prehnite after glauberite, 10cm tall	© 2007 FAI III

Prehnite after glauberite 8.6cm wide	© 2007 FAI III

This quarry has been productive of mineral specimens for years and well know for producing chocolate brown heulandite crystals up to about 3 cm and stilbite spheres up to 6 cm in diameter, some of them bright orange, but probably the best things the quarry has produced are specimens of prehnite casts after heulandite. The first pocket in the quarry was found back in the late 1980s Mark Bianchi and this pocket produced hundreds of specimens but of somewhat lighter colored prehnite that the more recent one in 2003 or 4. This pocket was actually a string of interconnected pockets that was collected over a period of about a year. It was located up about 15 feet on the east wall of the quarry and ladders had to be used to reach and work on the pockets. Several hundred good specimens were collected.
[James Zigras 2009]


Prehnite
USA
North Carolina, Catawba Co., Martin Marietta Quarry (11th Street Quarry), Hickory

Prehnite on Babingtonite, 3.5cm wide	© 2002, Keith Wood

We need someone to tell us about the specimens from this quarry.


Prehnite
USA
Pennsylvania, Lehigh Co., Coopersburg

Prehnite ~10cm wide	©

This locality only produced a few specimens. I managed to find one for sale in a collection at Wards in Rochester, New York years ago. I gave it to Arthur Montgomery and though he wrote the Minerals of Pennsylvania, he did not have one in his collection or in the collection he curated at Lafayette college in New Jersey and was very happy to have one. We need someone to tell us about the specimens from this quarry.


Prehnite
USA
Rhode Island, Providence Co., Cumberland, Manville Quarry (Todesca Quarry; Forte Brothers Quarry)

Prehnite, Tremolite & Axinite ~5mm wide	© 2009 Peter Cristofono

We need someone to tell us about the specimens from this quarry.


Prehnite
USA
Virginia, Augusta Co., Centerville, Quarry (MRDS - 10154716)

Prehnite on Quartz ~7.5cm wide	©

Prehnite ~2cm diameter	©

Prehnite ~4.5cm wide	©

Prehnite ~4.5cm wide	©

This quarry is famous for probably the best apophyllite specimens ever found in the USA. Sometimes these slightly complex flower like white Apophyllites of up to 15 cm were found growing on a base of nice green prehnite. These were all collected by amateur collectors and though the find produced several hundred specimens, they have all gone away and are highly cherished by those collectors who have them. John Medici got collected some of the best ones. The pocket also produced some few wonderful prehnite specimens. Some were complete spheres of prehnite that had ridges around their equator and have sometimes been described as flying saucers or Roman helmets. The often had find black needles of actinolite or some black hair like amphabole mineral growing in them, sometimes to the point that the prehnite was almost black. One collector who collected in the pocket said that part of the pocket was filled with masses of this hair like material and some matrix specimens that he removed from the pocked he could turn upside down and shake these prehnite balls out of the hair.


Prehnite
USA
Virginia, Loudoun Co., Conklin, Bull Run Quarry

Prehnite on Quartz 5cm tall	© Brander Robinson

Prehnite, Calcite & Apophyllite 3.5cm	© Brander Robinson

]]> Rock Currier Best Minerals P Mon, 19 Oct 2009 01:58:59 +0000 http://www.mindat.org/forum.php?read,82,138630,138630#msg-138630 http://www.mindat.org/forum.php?read,82,138630,138630#msg-138630 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?

Below are some first notes I have made about Pseudomalachite. This entry and thread has been made as a place holder for information that you will hopefully contribute about Pseudomalachite. This is my first attempt to do a 'best of' - article so i am looking forward a) to learn on this and b) to invite you all to step forward and contribute about this mineral.

If you have questions about the format that such an article should have, go the the welcome topic at the top of the Best Minerals forum and read what has been posted there. Also take a look at some of the more mature articles that have already been written like Rhodochrosite, Adamite, Millerite etc. You will need also to pick out other images of Pseudomalachite that will go into the article.

Last but not least i decided to try a bit different structure of the article as it has been used in other best of´s. I put this on discussion and it is no problem to reformat the article if your opinion tells me to do. I want to summarize the different habits/formations of Pseudomalachite at the top of the article and then before listing the localities describe the type locality and its specimens. Furthermore i first want to start with a restricted set of localities which seems to be the best - and forgive me that i am a bit focused on european (especially german) sites.

Feel free to give comments, critics etc. ... and as i am no native english speaker please tell me if i made mistakes and blunders (preferred by PM) ;-)

Cheers
Roger



Pseudomalachite
Cu₅[(OH)₂|PO₄]₂, Monoclinic

Silberbrünnle mine, GER, FOV 3 mm	© Stephan Wolfsried

The copper phosphate Pseudomalachite is a long time known mineral. The first mineralogist who described it as a discrete species was C.C. LEONHARD in the year 1812. LEONHARD had found a copper mineral in Libethen (L´ubietova, Slovakia) which he called 'Phosphorkupfer' due to its chemical composition. So one should expect that Libethen would be the type locality for Pseudomalachite but the story is much more difficult: In the same publication LEONHARD also mentioned the Rheinbreitbach occurrence but described the Pseudomalachite from there as 'blättriges Olivenerz' and assigned it to be Malachite. More than 20 years earlier Carl Wilhelm NOSE already recognized the mineral as being not malachite but a different species in his description of the Virneberg mine. KLAPROTH made a first analysis of this material in 1801 and HAUSMANN (1813) called it 'Pseudo-Malachite' - in summary reported by J.R. ZAPPE in 'Zappe´s mineralogisches Hand-Lexicon' 1817.

In 1831 GLOCKER introduced the name 'Phosphorochalcit' which is very common on 19th century labels of Pseudomalachite specimens - often varied as 'Phosphorkalzit' or 'Phosphorcalcit'. Diverse other names were created subsequently, as for instance 'Ehlit' and 'Prasin' (BREITHAUPT 1832), 'Lunnit' (Bernhardi 1839), 'Dihydrit' and 'Tagilith' (HERMANN 1846). To complete the confusion german mineralogist SCHRAUF summarized 1879 all copper phosphates under the group name 'Lunnit' including 'Dihydrit', 'Ehlit' and 'Phosphorochalcit'. It lasted until 1950 when the canadian mineralogist L.G. BERRY carried out analyses on diverse specimens in american museums which were labeled as 'Phosphorcalcit','Ehlit', 'Lunnit', 'Dihydrit' and 'Pseudomalachit' and found out that all were the same mineral. He reintroduced HAUSMANNs 'Pseudomalachit', engl. Pseudomalachite, which is still the valid species name today.

Isolated crystals	© Saul Krotki 2006

Aggregated crystals	© Stephan Wolfsried

Spherical	© Paul De Bondt

Botryoidal	© tb

The mineral itself may be not that spectacular as the history of its recognition and naming. The colour varies from blue-green via emerald green to dark green with an almost blackish tint. Pseudomalachite mainly occurs as botryoidal crusts or hemispherical aggregates built of microcrystals or as reniform, botryoidal or massive aggregates with a radial-fibrous structure and concentric banding. Individual crystals are rare. They tend to be prismatic or tabular. At the type locality crystals up to 5 mm size were found. It is a typical mineral of the oxidation zone of sulphidic copper deposits.

References:
Berry, L.G. (1950): On Pseudomalachite and Cornetite. - Am. Min. 35, 365-385
Fuchs, H.J., Kalbhenn, S. & Muhr, M. (1986): Rheinbreitbach, mit Schlägel und Eisen - Bergbaugeschichte, Geologie, Mineralien. - Bode, Haltern.
Glockner, E.F. (1839): Grundriß der Mineralogie. - Nürnberg.
Hausmann, J.F.L. (1813): Handbuch der Mineralogie. - Göttingen.
Nose, C.W. (1789): Orographische Briefe über das Siebengebirge. - Frankfurt.
Schrauf, A. (1879): Über Phosphorkupfererze. - Zeitschr. Kryst . 4, 1-33.
Zappe, J.R. (1817): Zappe´s mineralogisches Hand-Lexicon. - Wien.

More references can be found at the mindat-page for Pseudomalachite.


The type locality

Virneberg mine (St. Josephsberg mine), Rheinbreitbach, Germany

A classic Virneberg Pseudomalachite specimen, 4.1 x 3.4 x 3.1 cm	© Rob Lavinsky

Geology and mineralization
The Virneberg mine is not only the type locality of Pseudomalachite but also the occurrence where the best and largest crystals worldwide originate. Situated about 3 km east of the township of Rheinbreitbach, not far from the River Rhine, the mine worked on a hydrothermal vein-type deposit hosted by Lower Devonian sandstones, siltstones and shales. The primary mineralization consists of mainly Chalcopyrite, some Galena, Sphalerite and Pyrite and Quartz as gangue mineral. During the Tertiary - about 25 million years ago - a remobilization occurred due to the thermal influence of basaltic magmatism. The ore vein was cut by a basaltic dyke then. This process may have been the cause for the formation of a deeply developed oxidation and cementation zone. Late and post Tertiary uplift and erosion caused the deposit finally to be near to the surface today. The oxidation zone reaches to about 120 m depth, the cementation zone has no sharp border to the primary ore zone and varies between 180 to 230 m where the unaltered primary ore was found. The oxidation and cementation zone produced a very rich and complex paragenesis of secondary minerals - and provided us with some of the best pseudomalachite specimens worldwide and much more. Beside the Pseudomalachite the occurrence was famous for excellent specimens of Native Copper and Cuprite var. Chalcotrichite.

History
The mine has a long history. It is indicated by archaeological finds that mining goes back at least to roman times in the 3rd and 4th century. The first documentation of the mine dates from 1604. The name Virneberg mine can be derived from the old word 'firn' which means old. It was introduced by 'Bergmeister' Christoff Frantz in 1668 to distinguish the mine from the nearby newer 'Im Siepen', later St. Marienberg' mine. In the 1630s mining ceased due to the influence of the Thirty Years' War. In 1694 mining started over again and lasted with more or less success until about 1794 when the French occupied the eastern shore of the River Rhine. During that period, around 1765, the mine´s name was changed to 'St. Josephsberg' which is the official name of the mine but was never really established.

The Rhodius brothers acquired the mine in 1820 and started with the processing of the old dumps by acid leaching. In 1840 the 'Regenten' shaft was sunk and in 1843 a depth of 112 m was reached. 1848s revolution in Germany caused the mining to cease again. The mine was sold then in 1853 to the 'Anonyme Gesellschaft für Rheinischen Bergwerks- und Hüttenbetrieb'. The 'Regenten' shaft was deepened to 132 m and the new 'Alexander' shaft was sunk to the same depth. In 1853 the highest copper ore production was achieved with 2,753 tonnes. A large processing plant was built to process the rich newly discovered ore reserves. The year 1854 marks the absolute peak of copper ore production: 2,753 tonnes were mined then. During the following years the recovery decreased leveling at about 1,000 to 1,600 tonnes per year. A large processing plant was built to be able to process the rich ore falls which had been accessed during that time. At the same time the mining had to move to the north of the mine where the ore was found less deep because the old 16 hp steam machine was not able to perform sufficiently anymore. These problems may have led to a change of ownership. In 1870 the english 'St. Josephsberg Copper & Lead Mining Company Ltd.' company took over the works but had no success.

The company handed the mine over to the also english 'Virneberg Copper-Mining Company' in 1876. From now on the technical development increased rapidly, starting with a 60 feet cornish pump and a new horizontal steam machine at the 'Regenten' shaft. Another steam machine was installed at 'Alexander' shaft which was also able to drive the crushers and other processing installations. Subsequently the two older shafts were put out of sevice and the new 'Hadley' shaft was sunk, named after Sir Alderman Hadley, chairman of the company. In 1877 the processing plant was newly built and in 1878 the 'Hadley' shaft was deepened to 160 m. The Virneberg mine employed 164 persons in 1877. The ore was brought to England for smelting - via the Rhine and Rotterdam to Swansea. About 3,000 hundredweights per month were shipped (approx. 155 tonnes).

In the following problems occured due to damage at the hauling and processing machines, the transport costs increased sigificantly and in January 1882 it was planned to stop mining. The mine director was able to convince the investors to carry on due to the increasing need for copper (electric current cables, phone wires etc.) and the 'Hadley' shaft was deepened again - this time to 220 m. But the high recovery costs and a decreasing price for copper on the world market doomed the mine. End of September 1882 the english company stopped the mining activities. For a short time small amounts of ore still were mined under the supervision of mining director M.K. Roskilley. In 1884 68 tonnes of ore have been
extracted. Roskilley finally closed the mine in 1886 and in 1902 A. Mannesmann purchased the mine from him. Some exploration took place but the mining never was resumed.

Crystal aggregates on matrix, FOV 6 mm	© 2005 M. Kampf

Crystal aggregate, 0.45 mm	©

Pseudomalachite from Virneberg mine
The Pseudomalachite from Rheinbreitbach shows a worldwide unique diversity of habit. The mine was the first wehere isolated Pseudomalachite crystals were found. They reached a size of up to 5 mm which still can be considered to be the largest of the species worldwide today. A very common formation at Virneberg are radial clusters of sheet-like crystals forming balls and botryoidal crusts with small crystal faces at the surface. Also reniform and spherical aggregates with acicular radial structure have been found frequently as well as botryoidal, spherical and concoidal masses with concentrical banding. The main accompanying mineral is Quartz which mostly forms the matrix of the Pseudomalachite specimens, but also occurs as thin layers of chalcedony and microcrystalline quartz resp. covering the Pseudomalachite aggregates.

Until the late 1980s the old dumps still produced nice Pseudomalachite specimens and also other mineral specimens. In the 1990s the area was fenced and used for a deer park. Most of the area of the former mine is in private property and new finds are almost impossible now. Pseudomalachite from Rheinbreitbach can be seen in numerous international mineral museums. Some very good specimens are for instance in the collection of the Mineralogical Museum of the Bonn University (Poppelsdorfer Schloss), the Aachen University (RWTH) and in the Museum of Natural History of Bern, Switzerland.

It should be noted that Pseudomalachite was also found in several other mines of this ore district, for instance Clemenslust mine, Aurora mine and Venus mine. The latter are situated near the village of Obererl which was formerly named 'Ehl'. This is where the old name 'Ehlit' for Pseudomalachit originates.

A very detailed description of the Virneberg mine and its minerals can be found in the german publication Fuchs, H.J., Kalbhenn, S. & Muhr, M. (1986): Rheinbreitbach, mit Schlägel und Eisen - Bergbaugeschichte, Geologie, Mineralien. - Bode, Haltern (GER), where most of the infos compiled in this article are taken from.

Compiled by Roger Lang, 2009.

Pseudomalachite
Australia
Mt Glorious Mine, Queensland
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Austria
Kohlberg Mountain, Lower Austria

We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Belgium
Salm-Château, Vielsalm, Luxembourg Province
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Chile
Manto Cuba Mine, Atacama Region
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Congo, Democratic Republic of
M'sesa deposit, Kambove, Katanga (Shaba)

Pseudomalachite, 67 mm	© Paul De Bondt

We need someone to tell us about the pseudomalachites from this locality infos/history about.


Pseudomalachite
Germany

Silberbrünnle Mine, Black Forest, Baden-Württemberg

Pseudomalachite, FOV 5 mm	© Stephan Wolfsried

Pseudomalachite, FOV 3 mm	© Stephan Wolfsried

We need someone to tell us about the pseudomalachites from this locality infos/history about.

Lichtenberg Copper Mines, Franconia, Bavaria

Pseudomalachite, 5 x 3 x 3 cm	©

Pseudomalachite, FOV 33 mm	© 2005 M. Kampf

We need someone to tell us about the pseudomalachites from this locality infos/history about.

Reichenbach, Odenwald, Hesse
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Obererl (Ehl), Linz am Rhein, Rhineland-Palatinate ('Ehlite')

Pseudomalachite FOV 2.5 cm	© Peter Haas

Pseudomalachite on Chalcedony, 77 mm	© Paul De Bondt

The Venus, Aurora and Minderberg mines near Obererl produced some very nice specimens similar to those of the Virneberg mine. The mines were active in the early 19th century so specimens from there are rare.

We need someone to tell us about the pseudomalachites from this locality infos/history about.

Virneberg Mine (St Josephsberg Mine), Rheinbreitbach, Rhineland-Palatinate (TL)

Pseudomalachite
Italy
Funtana Maggiore Prospect, Montresta, Sardinia
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Portugal
Miguel Vacas Mine, Pardais, Évora District
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Russia
Turjinskii Mine, Urals Region
We need someone to tell us about the pseudomalachites from this locality infos/history about.
Mednorudyanskoye Cu Deposit, Nizhnii Tagil, Urals Region ('Tagilite')
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
Slovakia
L´ubietová, Banská Bystrica Region
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
United Kingdom
Cornwall, England (maybe diverse pictures from different localities but summarized under Cornwall!)
We need someone to tell us about the pseudomalachites from this locality infos/history about.

Pseudomalachite
USA
Thornton pit, Gila Co., Arizona
We need someone to tell us about the pseudomalachites from this locality infos/history about.
Schuyler Copper Mine, North Arlington, New Jersey
We need someone to tell us about the pseudomalachites from this locality infos/history about.]]> Roger Lang Best Minerals P Wed, 08 Jul 2009 13:26:28 +0000 http://www.mindat.org/forum.php?read,82,130579,130579#msg-130579 http://www.mindat.org/forum.php?read,82,130579,130579#msg-130579
Clearly I need all the help I can get. This is a work in progress. Please be patient

Polybasite Display Collections

[(Ag,Cu)₆(Sb,As)₂S₇][Ag₉CuS₄] monoclinic and trigonal

This 4x6 cm blue irridescent polybasite turns blood red from internal reflections when held at the proper angle. The almost horizontal crystal at the extreme right shows these red lights (Helen Tyson photo, ex RWMW collection, ROM collection)	© RWMW

Single crystals of polybasite are unknown, it universally occurs as pseudo hexagonal tablets or rosettes to 6 cm¹. It occurs in low to mid temperature hydrothermal silver veins. It is associated with pyrargyrite, tetrahedrite, stephanite, and other silver and lead sulfosalts, silver, argentite, gold, various simple sufides,and with quartz. calcite. dolomite, barite. Oriented overgrowths of Stephanite and Chalcopyrite (see Arizpe below) have been noted². Often the crystals are small making for excellent micromounts. It is common in small quantities and rarely in large amounts. Of the Ruby Silvers only miargyrite is rarer. Fine specimens with crystals over a cm are quite rare, especially undamaged and not on black matrix. Such aesthetic specimens on matrix (minatures and larger) are worth over a thousand (US$) and as the specimen and crystals get bigger, to tens of thousands of dollars. Good silver minerals have always commanded higher prices.

Now at the dawn of the new millenium, due to the current IMA lattice site rules, the Polybasite group contains Polybasite, Pearceite, Selenopolybasite, Cupropolybasite and Cupropearceite. The ideal formula for the group is [M₆T₂S₇][Ag₉CuS₂X₂] with M = Ag, Cu; T = As, Sb; and X = S, Se, with all of the sulfur positions able to accept some selenium³ and the copper site able to accept some silver⁴.

An analysed Pearceite from Uchucchacua, 2.2 cm wide	© JF Carpentier 2009

Only Polybasite and Pearceite have been found in cm sized xls, the others are found only as study grade material or as a single museum specimen. Often sulfosalts in an arsenic antimony series, like the antimony rich Bournonite and Tetrahedrite are more grey and get blacker as the arsenic content increases to the point where you can't visually separate them from the arsenic dominant members (such as Tennantite and Seligmannite, repectively) which are quite black. Sadly you can't visually distinguish any of the minerals in the Polybasite group. If a locality has both arsenic and antimony, at least a probe analysis is required to distinguish Pearceite from Polybasite and both a quantitative probe and crystal structure analysis is required to identify the others. Since Parceite is rarer there is an incentive to label Polybasites as Pearceites. In 1987 I saw a small Polybasite from the Husky Mine in the Humboldt Museum in Berlin labeled as Pearceite and I have my doubts about some recently marketed Mexican Pearcites.

One of the four "Ruby Silvers" (Pyrargyrite, Proustite and Miargyrite are the other three), Polybasite was recognized as distinct in the early 19^th century and was named by Rose in the same journal that Einstein published his relativity theories nearly a hundred years later. He named it from the Greek πολύς, poly, "many" and βάσις, basis, "a base" in allusion to the many base elements (Cu, Sb, As) present, one more (Cu) than the other Ruby Silvers².

The saga of Polybasite in the 19^th and 20 ^th century has had many twists, turns and surprises. Like many sulfosalts the formula contains (Sb, As) indicating there is also probably an arsenic rich mineral with almost the same formula except for (As. Sb). This arsenic dominant mineral was recognized by Rose in 1833, and reasonably (I think) he called it Polybasite². It wasn't until 1896 that Penfield named the arsenic analogue Pearceite⁵. In the 20^th century Frondel, who had the habit of showing up at conferences and announcing results with no supporting data, saw that the x-ray powder patterns were nearly the same for both minerals⁶, but there were some extra diffraction lines with some crystals. Real "pearceite" had these extra lines, real "polybasite" did not. To make matters worse there were "polybasites" (antimony rich) that had such lines⁷ (Antimonpearceite) and arsenic rich "polybasites" that had no extra lines⁷ (Arsenpolybasite). So by the end of the 20th century there were four members of the polybasite group (Polybasite, Pearceite, Antimonpearceite, Arsenpolybasite). The tremendous improvement in computerised x-ray technology that occured in the late 20^th century finally allowed the deciphering of these extra lines in polybasites. By the mid 20^th century single crystal work recognized that such extra lines were usually due to crystal growth features called polytypes, but the ubiquitous twinning (actualy trillings to give the pseudohexagonal rosettes) in this group precluded sorting this out until the people got around to it in the new millenium. Fortunately the IMA decided in 1998 that polytypes were no longer a species definer, but they would grandfather those names already published. Thus the polybasite group narrowly missed expanding by over half a dozen as now the polytypes designated by numbers and letters after the name had to be all varieties! Thus there are two structural varieties of the antimomy rich polybasite (trigonal, with space group P321 and monoclinic with C2/c)⁸. Further the species antimonpearceite was replaced by the variety polybasite-Tac, arsenpolybasite-221 by pearceite-T2ac, arsenpolybasite-222 by pearceite-M2a2b2c, polybasite-221 by polybasite-T2ac, and polybasite-222 by polybasite-M2a2b2c^4.9 So now it would seem that we are back to 1896 with only two members of the polybasite group: Polybasite and Pearcite, repectively antimony and arsenic rich members. Perhaps the next century will take us back to 1833 with only Polybasite and lots of varieties (I hope).

However in many sulfosalts selenium can replace some or most of the sulfur. When the selenium dominates two of the sulfur sites we get the new species Selenopolybasite [(Ag,Cu)₆(Sb,As)₂(S,Se)₇][Ag₉Cu(S,Se)₂Se₂] from the De Lamar mine, Owyhee County, Idaho, USA.³. Although overall the sulfur dominates the selenium, it is the last two Se₂ lattice sites that creates the species according to current IMA rules. And of course there will be polytype varieties, so far only Selenopolybasite-Tac has been observed from the San Carlos mine, La Luz,Guanajuato, Mexico⁹. One should also expect a similar selenium pearceite analogues, but so far none have been observed.

Further there are silver deficient Polybasites with idealy only copper in one of the silver positions. So we get Cupropolybasite [Cu₆Sb₂S₇][Ag₉CuS₄] from the Silbak Premier Mine, Stewart, Skeena Mining Division, British Columbia Canada¹⁰. If the antimony dominant member can do this so should the arsenic dominant one and we get Cupropearceite [Cu₆As₂S₇][Ag₉CuS₄]¹⁰ from the Sarbaiskoe deposit (Sarbai; Sarbay Mine), Qostaney Oblysy (Kostanai [Kustany] Oblast'), Kazakhstan. Both of these occured in the Tac polytype, so if more is found one can expect lots more varieties. Again one should expect the selenium analogues of these, but so far none have been observed.

Recently¹¹ the structure of Fettelite [Ag₆As₂S₇][Ag₁₀HgAs₂S₈] was found. As can be seen from the fomula the first layer in the formula is the same as in the polybasite group formula. So either Fettelite is a related mineral or the polybasite group should be redefined to include it. Fettelite occurs as tiny pseudohexagonal twins resembling polybasite and much of the marketed Fettelite is in fact polybasite

A ~2mm Fettelite crystal group from the type locality	© D. Harries

1) Anthony et al., Hanbook of Mineralogy, vol.1, pg 417, (1990)
2) Dana's System of Mineralogy, 7th ed., vol 1, pg 351-353, (1944)
3) Bindi, L., Evain, M., Menchetti, S.; Selenopolybasite, [(Ag,Cu)6(Sb,As)2(S,Se)7][Ag9Cu(S,Se)2Se2], a new member of the pearceite–polybasite group from the De Lamar mine, Owyhee County, Idaho, USA. Canadian Mineralogist, 45, 1525-1528. (2007)
4) Luca Bindi and Silvio Menchetti; Adding further complexity to the polybasite structure: The role of Ag in the B layer of the -M2a2b2c polytype. American Mineralogist, 94, 151-155 (2009).
5) Dana's System of Mineralogy, 7th ed., vol 1, pg 353, (1944)
6) Ibid. pg 355
7) Frondel, Am. Min. 48, pg 565 (1963)
8) Evain, M., L. Bindi and S. Menchetti; Structural complexity in minerals: twinning, polytypism and disorder in the crystal structure of polybasite, (Ag,Cu)₁₆(Sb,As)₂S₁₁. Acta Cryst. B62, 447-456 (2006).
9) Bindi, Luca, Michel Evain, Paul G. Spry, and Silvio Menchett; The pearceite-polybasite group of minerals: Crystal chemistry and new nomenclature rules. American Mineralogist, 92, 918-925 (2007).
10) Bindi, L., M.Evain, P.G.Spry, K.T. Tait, S. Menchetti; Structural role of copper in the minerals of the pearceite-polybasite group: the case of the new minerals cupropearceite and cupropolybasite: Mineralogical Magazine 71,641-650 (2007)
11) Bindi, L., Keutsch, F.N., Francis, C.A., Menchetti, S. (2009): Fettelite, [Ag6As2S7][Ag10HgAs2S8] from Chanarcillo, Chile: Crystal structure, pseudosymmetry, twinning, and revised chemical formula. American Mineralogist, 94, 609-615.




Polybasite
Canada
Yukon Territory, Mayo Mining District, Galena Hill, Elsa,Husky Mine, Stope 302

At over 4 cm these are the largest polybasite rosettes and and at 3,5 cm the largest single crystal ever recovered at the Husky Mine (Helen Tyson photo, ex Little Joe Weinholtzner, ex Mark Mauthner, ex RWMW collection, ROM collection)	© RWMW

There is little to no arsenic at Husky and all those x-rayed and probed have been end member Polybasite and with no polytypism observed¹. The irridescence of these pieces is truly remarkable, but sadly darken with age². Another truly remarkable property is that when held at a certain angle under strong light the irridescence disappears and the basal face turns blood red. Recently Chi Ma and George R. Rossman at Caltech showed that the same irridescent coating on Husky Stephanite contained no copper disproving the folklore that the coating was Bornite or Covellite.


In spring 1977,"Little Joe" Weinholtzner and Rod Shiletto collected some of the world's finest Polybasite and Stephanite from Stope 302 of the Husky Mine. Sadly Rod Shilleto died the following year and some of his pieces were given to friends as in memoriam gifts³.Some of the other miners there at the time gave wives and girlfriends these irridescent crystals for buttons and broaches. These delightful crystals even made it into folk art. In one such piece they were glued onto a set of mounted antlers³! There were occurrences of these irridescent crystals in other stopes, and indeed other mines in the camp, but little was saved.

Rod Tyson got there in1978 and Little Joe let him select two little pieces from a beer mug whose loose contents were poured out onto a bed. Rod got them out of the beer mugs and into specimen boxes.Rod was more successful with the Shilleto family and got a few small miniatures and quite a few thumbnails which he brought to market³. Word soon spread and people began making a pilgrimage to Little Joe's to photograph and marvel at the specimens. Someone told Little Joe that one of the specimens was worth $8,000.00 and Little Joe decided that this small collection would be his retirement nest egg. Many tried to pry them out of Little Joe and many failed. Finally when Mark Mauthner was in the Yukon looking for crystallized gold, he made the pilgrimage too. He and Little Joe got on well and it turned out that Little Joe had worked with Mark's father years early at the Husky. Little Joe trusted Mark and when he found out that Mark was well connected in the specimen community, he asked Mark to market his collection². One small cabinet (pictured above), a few miniatures and three dozen thumbnails and well over a hundred micros and kerbles were in the collection. The best of these polybasites were sold for many thousands of US dollars to well over ten thousand dollars. I was lucky enough to get a few of the best pieces from Mark. Shortly after Mark's success, Rod Tyson phoned the Shilletos and they agreed to sell the rest of what they had for roughly Mark's appraised value. Again there were a few small miniatures and more thumbnails³.

The mine following hydrothemal veins in greenstone is now closed and water filled and is slowly freezing. Like many northern mines it is in permafrost and had to be timbered well. Once a shaft was driven the permafrost began melting and rock falls were common. There was even permafrost in the 302 stope³.


1) Gary Ansell, private communication.
2) Mark Mauthner, private communication.
3) Rod Tyson, private communication
Ref.: (in part): Rocks & Min.:64:489.

Polybasite
Germany
Baden-Württemberg, Black Forest, Wolfach, Oberwolfach, Rankach valley, Clara Mine

3 mm polybasite from the Clara Mine	© D.Preite

Sebastian Möller has contributed the following about the Clara Mine and its polybasites.

"The polybasite minerals from Clara Mine are the former species Polybasite, Antimonpearceite (polybasite-Tac) (the most abundant one, xls up to about 1 cm, I have some ore specimen with xl fragments of 3-4 cm) and pearceite.

The Clara Mine is the only mine still active in the Black Forest. Now over 400 mineral species have been discovered at the Clara, some of them being unique. The mine is type locality for about 20 species. It has been worked without a gap from the 1880'ies, but sporadic mining occured much earlier. There is the legend of a small mining town called Benau (mineral benauite) on the mountain above today's mine. It was destroyed by a flashflood in 11^th or 12^th century and the legend tells that it was due to the habitants worshipping a golden calf ! Up to the 19^th century silver ore (probably fahlore, which now is really abundant) and maybe copper ores were mined. In the 19^th century production of baryte began. It was then used mainly for paints, later on for paper additives and medical products as well as a barium ore for fireworks. In 20^th century fluorite production began.

There are three main vein systems of about 1 km in length and up to 8-10 cm in width: 1) a baryte vein with minor fluorite and chalcopyrite, fahlore (tetraedrite-tennantite) and even Sb sulphides (polybasite-Tac, pyrargyrite, proustite); 2) a fluorite vein with minor sellaite; 3) a diagonal trum with mainly fluorite and minor baryte, often silicified areas with quartz and minor galena/chalcopyrite ore. These veins are situated in a melange of rocks containing mostly gneisses, with minor silicified serpentinites, basic rocks and felsic granulites."

Polybasite
Mexico
Zacatecas,Mun. de Fresnillo,Fresnillo de Gonzalez Echeverria (Fresnillo)

Polybasite and Calcite, 8.8 cm wide	© Rob Lavinsky

Polybasite
Mexico
Guanajuato, Mun. de Guanajuato

Polybasite and Calcite, 10 cm wide	©

Polybasite
Mexico
Sonora, Mun. de Arizpe, Arizpe, Chispas Mine (Pedrazzini mine)

3 cm Polybasite crystal in rosette with Chalcopyrite

Polybasite
Morocco
Souss-Massa-Draâ Region, Ouarzazate Province, Boumalne-Dadès, Imiter Mine

Polybasite xl, 0.75mm	© Steve Rust

Initially there were few Polybasite specimens from Imiter, but now there is lots of material available. Unfortunately the xls are all micros, but the associations with xanthoconite and proustite make spectacular micromounts. Have any of these been analysed? The arsenic present in proustite lets one suspect the presence of Pearceite here. Many "Fettalites" from here are in fact polybasites

Polybasite
Peru
Lima Department, Oyon Province,Uchucchacua Mine

Arsenic rich Polybasite from Uchucchacua, 7.5 cm high

Both arsenic and antimony occur at Uchucchacua and so do both Polybasite and Pearceite. To know which is present, they must be analysed.]]> Rob Woodside Best Minerals P Thu, 09 Jul 2009 11:45:54 +0000 http://www.mindat.org/forum.php?read,82,129408,129408#msg-129408 http://www.mindat.org/forum.php?read,82,129408,129408#msg-129408
Ideally what we want to know about each significant mineral from each locality is:

1. What is the largest crystal of the mineral that the locality has produced?
2. What do the best specimens from this locality look like and where can one be seen?
3. Does the locality produce a variety of different kinds of specimens of this species, and what do the best of each type look like and how many of them were found etc.
4. What are the associated minerals found with this species and what is its geological setting?
5. How abundant are these specimens and when were they found? A type locality? In other words, how rare are they.
6. How do they compare to other specimens of the same mineral from other localities?
7. How much is it worth. This should probably be optional, but in cases where specimens are worth thousands of dollars we should probably say something of the value of these things.
8. What kind of care and feeding do these specimens require? Are they delicate, radioactive, unstable, color changeable etc.?
9. Are the specimens commonly faked, and if so, how to tell if they are?
10. Are there any interesting stories relating to the collecting of these specimens or their discovery as a new mineral?

Of course this is in reality impractical, but if we keep these questions in mind, we will do a lot better job when writing about them.]]> Rock Currier Best Minerals P Fri, 06 Mar 2009 11:23:03 +0000 http://www.mindat.org/forum.php?read,82,122552,122552#msg-122552 http://www.mindat.org/forum.php?read,82,122552,122552#msg-122552

Pääkkönenite Rare species collections.
Sb₂AsS₃
Pääkkönenite is a fairly rare mineral and some number of specimens were discovered as an association with the spectacular new kermesites (2002) from China. I think these have proved to be the best specimens discovered thus far. To put things in perspective, here are some comments from long time rare species dealer Tony Nikishire. “We had some pääkkönenite some years ago (1994), discovered inadvertently in some stibarsen specimens from Pribram that we were being analyzed. …It’s a “Two Star” rarity (3 is the rarest) relative to the rest of the species…but likely more common than more people think as it easily passes for other things and escapes detection unless some analytical process is used to find it. I don’t think it could command the prices it did 8 or 10 years ago.” There are currently about six localities where this mineral has been found.₁
1 Tony Nikishire, Excalibur Mineral Corp. personal communication 2002.
[Rock Currier, 8 December 09]


Pääkkönenite
China
Henan, Nanyang Prefecture, Xixia, Lushi, Lushi Antimony Mine.

Pääkkönenite, 3 cm across	© Knut Eldjarn

Pääkkönenite FOV 5mm	© Leon Hupperichs

This locality is better known for the large world class kermesite crystals that it has produced than its pääkkönenite specimens. So far it would appear that the pääkköneite has been recognized on only a few specimens of well crystallized stibnite and kermesite from the locality. The specimen was trimmed a little to make the it more saleable before it was known that the specimen contained the rare mineral. The original specimen on which this new find was discovered was on a crust were well crystallized stibnite and kermesite were associated with sharp micro crystals of yellow valentinite. The Pääkkönenite on this specimen consists of a shiny crust of the mineral which under 10 to 30 x magnification can be seen to consist of polygonal tiles consisting of shiny flat lying, subparallel bundles needle like crystals. The other minerals were found growing on the pääkkönenite. This would be only the third locality for this particular mineral and probably the best so far. Undoubtedly much more of the mineral has been mined and gone unrecognized by the miners and thus far (Jan 2003) the Chinese dealers who have visited the mine. A few hundred specimens of this material would completely saturate the market because the market for rare species is rather thin.
[Rock Currier, 8 December 09]


Pääkkönenite
Czech Republic
Bohemia, Pribram
Pääkkönenite has been found here in stibarsene “This rare species occurs as submicroscopic bundles of straw-like prismatic crystals in stibarsen. It was found on a single specimen mined prior to 1940; the mineral has been confirmed by both X-Ray and microprobe analysis. Tiny fragments in a capsule @ 60.00; matrix specimen with copies of three or more photomicrographs from 0.4 to 1.5 cm @ 85.00, 120.00, 150.00 and 200.00 each.”₁ Prices are in $US.
1 Tony Nikishire, Excalibur Mineral Corp. personal communication 2002.
[Rock Currier, 8 December 09]


Pääkkönenite
Finland
Seinäjoki Ore Region, Kalliosalo Deposit
“The mineral occurs in irregular grains up to 0.4 mm in size in the Kalliosalo deposit, associated with arsenopyrite and loelligite. …Color dark gray, streak gray with a slight brownish tint, luster metallic. Readily scratched by a Cu needle, brittle, one cleavage. Fine polysynthetic twinning present. In reflected light pale gray, strongly anisotropic, birefringence weak. … Internal reflections bright red. …The name is for the late Viekko Pääkkön, who studied ore deposits of the region. Type material is at the Fersman Mineralogical Museum, Acad. Sci. USSR, Moscow.”₁
1 American Mineralogist, Vol. 67, 1982 p. 858.
[Rock Currier, 8 December 09]


Pääkkönenite
USA
California, San Diego Co., Cryo Genie Mine

Pääkkönenite. a cm size xl spray of 9mm in Quartz	© Rob Lavinsky

The specimen pictured above is from a pegmatite mine much better known for the pink and green tourmaline specimens it produces. Pääkkönenite has recently been identified from there in only a few specimens (less than six), all inside of quartz crystals. Tony Kampf of the Los Angeles Co. Museum of Natural History identified the mineral. A specimen at the Los Angeles County Museum is a tabular doubly terminated quartz crystal containing an eye visible spray of shiny black spray of needles included mostly in the quartz but with a few of them sticking out of one of the broad flat prism faces.
[Rock Currier, 8 December 09]]]> Rock Currier Best Minerals P Thu, 08 Jan 2009 11:45:02 +0000