http://www.mindat.org/msgboard-79.html Fri, 27 Nov 2009 02:00:22 +0000 Phorum 5.2.8-RC1 http://www.mindat.org/forum.php?read,79,151071,151071#msg-151071 http://www.mindat.org/forum.php?read,79,151071,151071#msg-151071


Mirabilite
Na₂SO₄·10H₂O monoclinic

Mirabilite, Soda Lake, Carrizo Plain, San Luis Obispo Co., California, USA	©

Mirabilite is a water soluble evaporate mineral that forms in many salt lakes, often on a seasonal basis when the temperature and salt content of the brine is favorable to its formation. It is not a stable mineral under normal conditions and when removed from the brine will under most conditions quickly begin to loose its water and a crust of sodium carbonate (Thenardite) will start forming on its surface. If you quickly placed the specimens in an ice chest at about 0 degrees you could preserve this mineral intact. In the space of an hour or so the nice specimens you have collected will be just a pile of white Thenardite fragments.


Mirabilite
USA
California, San Luis Obispo Co., Carrizo Plain, Soda Lake

Mirabilite	©

Mirabilite	©

Mirabilite	©

Mirabilite	©

Mirabilite can be sometimes found at this locality when conditions are favorable for its growth in the mud just below the salt crust of this sometime dry lake. Collecting there is one of the dirtiest collecting experiences that field collectors will likely ever encounter. Use this link if you would like to read about collecting Mirabilite, Thenardite and other minerals at Soda Lake.
[Rock Currier 2009]]]> Rock Currier Best Minerals M Sun, 06 Sep 2009 01:45:25 +0000 http://www.mindat.org/forum.php?read,79,147007,147007#msg-147007 http://www.mindat.org/forum.php?read,79,147007,147007#msg-147007

Muscovite

KAl₂[(OH)₂|AlSi₃O₁₀] Monoclinic

Minas Gerais, Brazil 6 cm	© Rob Lavinsky

Thin sheets of muscovite (showing it's property of flexibility) are commonly available, but good examples of crystals are not particularly common. Almost all of the specimens are from pegmatites, with Brazil being the most prolific. Also sometimes sheets of muscovite with various inclusions are sold.

The earliest use of muscovite was for jewelry. The first major use of muscovite was as a window pane for wood and coal burning stoves. Currently sheet mica is used as an electrical insulator and in electronic capacitors. It is also used as a "glitter" component in cosmetics.

Muscovite is found in all types of rocks. It occurs as a detrital component in sandstones and arkoses, is a major component in metamorphic rocks (mica schists), as an accessory mineral in granites and pegmatites and the variety sericite is common in many hydrothermal deposits. Most commercial production is from large books in pegmatites.


The most common forms are hexagonal crystals, but you can also get star twins, and aggregates forming balls. The largest known crystal of muscovite came from the Purdy mica mine in Ontario Canada. It measured at least 2.4m long and 1.5m in diameter.


Argentina
Catamarca, Papachacra

10 cm	© Rob Lavinsky

10 cm	© 2008 Steve Hardinger

Australia
Victoria, Lake Boga granite quarry

3 mm	© Judy Rowe

Austria
Salzburg, Krautgarten Mt.

10 cm	© Gerd Stefanik

Brazil
Espírito Santo, Mimoso do Sul Mine

12 cm	© Kuno Stoeckli

Brazil
Minas Gerais

5 cm	© Rob Lavinsky

5 cm	© Safaa Yu

5 cm	© Rob Lavinsky

8 cm	© Rob Lavinsky

3.5 cm	© Martins da Pedra

Fuchsite 6 cm	© JSS

Brazil
Minas Gerais, Divino das Laranjeiras

10 cm	© Rob Lavinsky

Brazil
Minas Gerais, Cigana claim

6 cm	© Martins da Pedra

Brazil
Minas Gerais, Virgem da Lapa

4 cm	© CCURTO08

Canada
Ontario, Nipissing District

8 cm	© Russell G. Rizzo

Germany
Rhineland-Palatinate, Wannenköpfe

2 mm	© frank de wit

3 mm	© Fred Kruijen

Germany
Saxony, Neumark, Diabase quarries

var Astrolite 2.5 cm	© M. Adelt

Italy
Aosta Valley, Prabornaz Mine

var Alurgite 4 cm	© Paolo Grosso

Madagascar
Fianarantsoa Province,Malakialina pegmatites

4 cm	© ARLIGUIE M

Pakistan
Baltistan, Shengus

3 cm	© Christian Bracke

Portugal
Viseu District, Real quarry

3 cm	© Rui Nunes 2008

USA
California, Pack Rat Mine

12 cm	© Rob Lavinsky

USA
Maine, Mt. Apatite, Maine Feldspar Quarry

5 cm	© 2007 D. Levesque

USA
Maine, Lord Hill Quarry

5 cm	© 2007 Steve Bonney

USA
New Hampshire, Palermo No. 1 Mine

8 cm	© 2006 Peter Cristofono

USA
New Mexico, Harding Mine

3 cm	© 2007, JGW

9 cm	© Rob Lavinsky

USA
North Carolina, Rist Mine

8 cm	© Rob Lavinsky

USA
North Carolina, Lincoln Co.

Inclusions of garnet, rutile? 10 cm	© 2003 John H. Betts

USA
South Dakota, Diamond Mica Mine

8 cm	© Rob Lavinsky

Pseudomorphs of Muscovite

Bolivia
Potosí Department, Llallagua

after orthoclase 10 cm	© Rob Lavinsky

Japan
Kyoto Prefecture, Kameoka City

0.7 cm	© 2008, JGW

Variety sakura-ishi "cherry blossom stone" pseudomorphs after cordierite crystals.


USA
Arizona, Willow Spring Ranch

sericite after tourmaline 3 cm	© 2001 John H. Betts

USA
Maine, Noyes Mountain Quarry (Harvard Quarry)

sericite pseudomorph after tourmaline 2.5 cm	© 2001 John H. Betts

USA
New Hampshire, Atwood Mine

Pseudomorph after schorl 6 cm	© 2007 Peter Cristofono

]]> David Von Bargen Best Minerals M Thu, 30 Jul 2009 16:21:36 +0000 http://www.mindat.org/forum.php?read,79,143977,143977#msg-143977 http://www.mindat.org/forum.php?read,79,143977,143977#msg-143977



Meyerhofferite
Ca₂(H₃B₃O₇)₂· 4H₂O triclinic

1.Meyerhofferite after Inyoite, Mt. Blanco Mine, Death Valley, California ~11cm wide	©

Of the various kinds of Meyerhofferite specimens found thus far it would appear that the ones collectors most favor are the pseudomorphs after Inyoite (picture #1). I may be biased in my view because early in my youth I helped dig a wonderful pocket of these specimens in the Mt. Blanco mine in Death Valley. This mine also produced specimens of the other common type of Meyerhofferite, or primary Meyerhofferite as we call it. This is the cross hatched/reticulated almost honey comb variety that is exampled in picture 3 from Turkey below. I think that Turkey has produced the best of these specimens. Specimens containing crystals of this kind of Meyerhofferite up to 4 cm are said to be known.¹
1.Handbook of Mineralogy, Anthony, Bideaux, Bladh and Nichols Vol V. p450.
[Rock Currier 2009]


Meyerhofferite
Argentina
Salta, Sijes, Monte Azul deposit

2.Inyoite in/on Meyerhofferite, 17.7cm wide	© Rob Lavinsky

2.5.Meyerhofferite in Inyoite ~4.7cm wide	© Rob Lavinsky

All the specimens I have seen of Meyerhofferite I have seen from this locality are slightly altered crystals of Inyoite where enough of the Inyoite has been replaced by tiny white prismatic crystals of Meyerhofferite to render their usual transparent white/translucent nature mostly white. But in reality the bulk of the specimen is still Inyoite. Some of these specimens are very handsome and some people may feel that these are the most desirable kind of Meyerhofferite specimens to have. The one shown here, picture #2 is about as good as they get. Some very few specimens show both the unaltered and partially altered crystals on the same specimen. A very few others show transparent unaltered Inyoite with little sparkling whitish primary Meyerhofferite crystals growing in their interiors (picture 2.5) This deposit is is a little surface working where some heavy equipment has gone in and made some trenches and mined out some tons of material for processing into borate products. Several lots of Inyoite specimens were collected by various people, mostly visiting American geologists that worked for the company that was exploiting the deposits for industrial use. Probably the best material collected was done by Joe Siefke who was working for US Borax at the time. Probably less than 500 specimens total were collected before the pocket area was mined out. But at least a few specimens were saved from the mill and these will be with the collecting fraternity, probably for hundreds of years, long after this little barren patch of the Altiplano is long forgotten.
[Rock Currier 2009]


Meyerhofferite
Turkey
Marmara Region, Balikesir Province, Bigadiç

3.Meyerhofferite, 12cm wide	© Marco Barsanti

4.Meyerhofferite, 9.5cm wide	© jm.CLAUDE

It would appear that many wonderful borate specimens have been produced at Bigadiç, one of the oldest known Turkish borate localities. They certainly appear to have produced the best specimens of the crosshatched/reticulated varieties. We need someone to tell us about the Meyerhofferite specimens from this locality.


Meyerhofferite
USA
California, Inyo Co., Death Valley, Furnace Creek District, Black Mts, Mount Blanco mine

5.Meyerhofferite after Inyoite ~12cm wide	©

6.Meyerhofferite after Inyoite ~7cm wide	©

7.Meyerhofferite after Inyoite ~6cm wide	©

8.Meyerhofferite ~4cm wide	©

9.Meyerhofferite ~3cm wide	© John Sobolewski

10Meyerhofferite FOV 15mm	© 2008 Jesse Crawford

11.Meyerhofferite, 5.3cm wide	© Rob Lavinsky

12.Meyerhofferite ~4cm wide	©

This locality is barely a mine, probably more accurately it should be called a prospect. It has a short little tunnel, less than 100 feet long with a couple of little crosscuts that branch to the right. It was in these little cross cuts, probably not more than 10 feet long that produced the wonderful specimens of Meyerhofferite pseudomorphs after Inyoite as well as a few specimens of the reticulated variety. The pockets of pseudomorphs that were encountered, probably no more than two or three pockets of less than a meter in extent produced all of the known specimens of this type. Probably less than 500 specimens all total, though one of them, a fine specimens measured perhaps ~50cm in diameter. The specimens from the tops of the pocket showed specimens of chalk white nature, pictures #5, 6, & 7, while those from the bottom had a more sparkling nature, picture #1 due to the present of tiny crystals well crystallized Meyerhofferite growing on the pseudomorphed crystals. Perhaps the largest of the pseudomorphed Inyoite crystals measured ~12 cm across.
[Rock Currier 2009]]]> Rock Currier Best Minerals M Sun, 05 Jul 2009 11:48:40 +0000 http://www.mindat.org/forum.php?read,79,141514,141514#msg-141514 http://www.mindat.org/forum.php?read,79,141514,141514#msg-141514 "...attached a thin copper wire to natural malachite bearing matrix.
They were next put into a copper rich solution and then by administering some form of electrostatic charge the malachite crystalized around the wire to form a stalagtite..."
I never heard about that, where are the scientific reports? I would love to read them.
Because for the 10 or 12 years ago fakes, I can tell you it was much more simple, it was crushed roughy malachite + glue on real broken stalactites or on pieces of wood" and that's it!
They had not the technic to do that (and is it possible to do that?) and it was more simple.
Now for the piece of wire inside, I confirmed I found some....but it is quite funny to read some scientific explanations of growing around and electrostatic... they just used pieces of wire to put in the hole of the stalactites broken!
When a stalactite is broken you have the hole inside and putting a wire inside just help to maintain it when you glue it.Only for that!
Now I'm maybe wrong about some scientific explanations but I just want to read the reports, I never heard about that.
So please for my knowledge, if anybody has a scientific report confirming 100% this technic, forward it to me.
Because a rumor is easy and destroying.
When I know how hard and dangerous sometime it is to travel to the sources.
I gave to Jolyon a small note to publish about my own small experience of traveller to Congo and some easy way to try to determinate if a stalactite is fake or not.
I have not the divine truth but I just try to bring my own experience to this topic.


In the past it was easy to go on the field in Congo, the mines were not working and the guys had easy access. Now for the last 5/6 years new private owners are mining and the access is closed.It will be difficult to have some photos but I will ask my guys if they can.And it is also maybe one year they didn't find any really good ones unfortunatly.
About the photos published, lets play the quizz but again it is a feeling, I can't be sure 100% on photos, I would say:
* 104633 from Debbie: should be real but maybe repaired with glue+malachite crushed on the 1/3 from the base
* Lawrie piece: can be fake
Debbie links:
*132897:no photo
*117571: real
*140554: should be real
*112: real
*89207: no photo
*97312: can be fake
Again, if you have any doubt, me I put the piece in acetone.

About the fake stalactites, there is not one locality especially because they could use a matrix from The Star of Congo Mine (SCM) and a broken stalactite from Kasompi....
But if you want a joke, one of the guys who made the 1st ones was called Baudouin and now when they show me a fake one (after yelling and explaining that they can loose more than they win...but they need money to feed the family...), I just tell them "I don't want your baudouinite....".
Baudouinite is the "official" name of the fake malachites on the local market of Lubumbashi....

In the last 2-3 years the Kasompi Mine (KM) has been the one producing most the stalactites on the market (I speak about real ones) but the quality was not as good as the ones from SCM, most of them were darker.
In the past, several mines in the Congo produced some fine stalactites: Lupoto, Luishia (fantastic velvet ones), Lukuni....

But the SCM has produced most of the best malachites, botryoidal or stalactites, in quality and in quantity.
This mine is fantastic for the diversity of shapes, colors (from light to dark), associations with chrysocollas.
Unfortunatly we don't see anymore significant pieces for the last 5-6 years because a private company is mining at the SCM and the security on the pit doesn't allow the guys to go there.

You can see on the market many pieces with a wrong label "Mashamba west Mine" (MWM) when it comes from the SCM.
The MWM has been famous in the past for its primary malachites producing some real crystal up to 6-8 cm, some great "flowers" of malachites, sometime combined to red gemmi cuprites, light green acicular malachite, orange barites...and what almost nobody knows, in 90-91's my father brought a 20 cm doble terminated crystal of azurites but completly oxydated from MWM.
Few weeks later began the civil war and since that time the mine is floatted!! But there is a pocket of azurites still waiting under a green lake of cooper water....
All the Kolwezy are has also produced the very quality of malachite rough for the carving and the jewellery.

Hope these informations from my own experience in the Congo will help you.

Christophe Gobin]]> Rock Currier Best Minerals M Sun, 14 Jun 2009 05:11:45 +0000 http://www.mindat.org/forum.php?read,79,130896,130896#msg-130896 http://www.mindat.org/forum.php?read,79,130896,130896#msg-130896

Millerite
NiS Trigonal

Millerite from the Thompson Mine, Canada, 2.7X6.3X1.5cm	© Cindy Hasler www.canadianminerals.net

A nickel sulfide mineral (NiS) found in carbonate veins, or as an alteration product of other nickel minerals. Other occurrences are in meteorites and as a sublimation product on Vesuvius. Millerite forms pale brass-yellow crystals that belong to the hexagonal system.

Millerite
Australia
Western Australia, Goldfields-Esperance region, Agnew (Perseverance Deposit)

5.2x4.2cm	© Rob Lavinsky

7x4cm	© JF Carpentier 2007

One of the largest nickel sulfide deposits in the world with reserves of 45 million tons at 2.05% nickel.
We need someone to tell us about the specimens from this locality.

Millerite
Belgium
Limburg Province, Genk, Winterslag Mine

FOV 4,5cm	© Nilis

FOV 0,3cm	© Richard De Nul

In concretions found on the dumps of the coal mines of Winterslag very nice up to 5 cm long Millerite crystals have been found over the years. Winterslag mine is located close to the provincial town of Genk.

Millerite
Canada
Manitoba, Moab-Setting Lakes area, Thompson Mine (Thompson T-1 Mine; Thompson Open pit)

2.7X6.3X1.5cm	© Cindy Hasler www.canadianminerals.net

7X4X1cm	© Cindy Hasler canadianminerals.net

7X4.5X2cm	© Cindy Hasler www.canadianminerals.net

9.2X3.4x4.3cm	© Cindy Hasler www.canadianminerals.net

An open pit nickel mine owned by Inco, Ltd. Started about 1986. Located on the Thompson nickel belt. The acicular Millerite was all frozen in Calcite and etched out using hydrochloric acid (info Rob Woodside)
Can you tell us more about specimens from this locality?

Millerite
Canada,
Québec, Sherbrooke Co.,St-Denis-de-Brompton, Orford Nickel Mine

FOV 1,8cm	© Tony Peterson

FOV 0,23cm	© Scott Whittemore

Can you help us with information on specimens from this locality?

Millerite
Canada
Ontario, Sudbury District, Strathcona Mine

4,4x3,8x1,8cm	© Rob Lavinsky

7x4,5cm	© G. van der Veldt

A nickel mine located in Levack Township. The ore is in the Sudbury nickel irruptive, a giant polymetallic deposit (hosted within one of the Earth's largest impact craters with a diameter of 250 km). Workings are deeper than 3,000 feet (> 1,000 meters). Millerite usually occurs as massive veins. The most attractive specimens are those where the silvery Millerite vein runs through massive chunks of golden coloured Chalcopyrite.
Can anyone help us with information and photographs of specimens from this locality?

Millerite
Czech Republic
Bohemia (Böhmen; Boehmen), Central Bohemia Region, Kladno, Ronna Mine

4,9x2,6x2,5cm	© Rob Lavinsky

FOV 0,6cm	© 2006 M. Kampf

Coal mine.
Can anyone help us with information and photographs of specimens from this locality?

Millerite
France
Lorraine, Moselle, Lorraine coal basin, Forbach, Stiring-Wendel, Simon Mine

19x15x9cm	© R. Lang 2009

FOV 2cm	© R. Lang 2009

Millerite from the Saar-Lorraine coal basin

The occurrence of Millerite led to the the first scientific research on Saar coal basin minerals by STEININGER (1819). He describes hairlike crystals associated with siderite/ankerite ("Braunspath" ), pyrite and sphalerite. They were found in a newly opened coal mine in the "Friedrichsthal" in 1806". JORDAN (1854, cited by GUTHÖRL 1963) also reported Millerite formed in crevices of sphaerosiderite on siderite crystals. At that time Millerite was known from the Jägersfreude, Dudweiler, Sulzbach, Friedrichsthal and St. Ingbert mines. Also during railway construction Millerite was found. Probably the best specimens were recovered at the Brefeld mine. GUTHÖRL (1963) reports that he obtained Millerite specimens from that mine with needles up to 60 mm lenght from the Hoffman collection for the geological collection of the Saarbrücken mining academy in 1944. They were associated with Ankerite and Chalcopyrite. Unfortunately most of the samples were lost during a bombing in WW II. GROTH (1878) also describes Millerite from the Dechen and Dudweiler mines occurring in needles of more than 1 Zoll (inch) lenght.
The most common association of millerite in the Saar coal basin is with Siderite/Ankerite, Dolomite and Chalcopyrite. Specimens with other sulfide minerals like Galena or Sphalerite are more rare. According to GUTHÖRL Millerite was found in almost all mines of the region except Ensdorf/Griesborn, Viktoria and Velsen mines. As a result of the closure of almost all mines no more finds are to be expected. Around 1980 a few Millerite samples were found at the dumps of the Camphausen mine by the contributor (Roger Lang). They consisted of lustrous sprays of acicular Millerites in Siderite covered vugs in siltstone/shale. As most of the dumps are landscaped or covered today new finds are almost impossible.
The millerite occurrences of the french side of the coal basin were not described by GUTHÖRL. In the early 1980s some millerite specimens from Lorraine were offered at a local mineral show. One sample was acquired by the contributor. It was told to originate from the Simon/Wendel mine between Petite-Rosselle and Forbach near the german-french border. It is a large specimen with Siderite crystals covered partly by hairlike Millerite crystals up to approx. 3 cm lenght, accompanied by small Chalcopyrite crystals. Consequentially also the french part of the basin can be considered to have been an important source of millerite specimens in the region.
Millerite specimens from the Saar coal basin are preserved in the geological collection of the Saarland. The collection is based at Landsweiler-Reden at the former Reden mine site. It is a merge of the geological collection of the Saarland University with the inventory of the geological-mineralogical collection of the Deutsche Steinkohle AG (DSK, the successor of the collection of the mining academy (Bergingenieurschule Saarbrücken), later Geologische Sammlung der Saarbergwerke AG). The collection is not at display at the moment (April 2009). According to GUTHÖRL other specimens were kept at the departments of mineralogy at Berlin, Munich and Heidelberg universities.
[Roger Lang 2009]

Mineralogy, geology and mining history of the Saar-Lorraine coal basin

The coal of the Saar coal basin has been mined for a long time with a first reference from the 14th century. The coal seams are of carboniferous age and were formed in an intramontane through and they are of limnic origin (in contrary to the Ruhr coal which is paralic). The seams are hosted by conglomerates, sandstones, siltstones and shales of the Westphalian C and D to the Stephanian C. Their average thickness is approx. 1,7 to 1,8 m.
The area where the coal was mined extends from Faulquemont and Folschviller in the southwest via Merlebach (all in Lorraine, France), to the german side with the Warndt, Völklingen and Saarbrücken to Neunkirchen and Bexbach in the northeast. During the 19th century hundreds of shafts were working and at the end of the century larger mines were established like the sites of Camphausen, Brefeld und Maybach. Due to the technical development the extraction tonnage increased - only interrupted by World War I, the economy crisis in the 1930s and shortly after World War II - to reach a peak of 17.2 million tonnes in 1955. From 1957 the coal crisis - caused by the increasing use of oil and the cheaper imported coal - led to the close-down of numerous mines and to a consolidation of smaller sites to larger combined mines. In
1968 only 5 mines were left: Ensdorf, Warndt/Luisenthal, Göttelborn, Reden and Camphausen. The latter was closed as a discrete mine and consolidated with Reden and Göttelborn to form the "Verbundbergwerk Ost" (combined East mine) in 1995. This mine was equipped with the worldwide highest headframe - and closed in 2000. In 2005 mining at the Warndt/Luisenthal mine ended and after the closing of the privately owned small scale Fischbach mine end of 2008 only one active mine was left: the "Bergwerk Saar"(Saar mine) in Ensdorf which is operated by the Deutsche Steinkohle AG (DSK). Due to mining-induced seismicity resulting in earthquakes the extraction of the Saar mine had to be reduced in 2008 from 15.000 t per day to almost a third. The closure is determined for the year 2012. Over the centuries approx. 1.5 billion tonnes of coal have been extracted.
During active mining quite a lot of mineral specimens were recovered in the Saar coal basin. The sand- and siltstone host rock contains smallscale hydrothermal mineralization in clefts and small veinlets as well as the coal itself locally was mineralized by hydrothermal fluids. Similar to other coal basins also ironstone geodes - consisting of clayey siderite concrections - contained epigenetic mineralization in shrink crevices. The mineralization is quite uniform. Most common non-metallic minerals are carbonates like Siderite, Dolomite, Ankerite and Calcite, also Baryte and Quartz occurred. Sulphides are Pyrite, Marcasite, Sphalerite, Chalcopyrite, more rare Galena and Linnaeite. An overview of the minerals of the Saar region coal mines was given by WILLERT (1914, cited by GUTHÖRL 1963). Most specimens were not very spectacular and can be looked upon as locality specimens but the Millerite samples were outstanding.
[Roger Lang 2009]

Millerite
Germany
North Rhine-Westphalia, Sauerland, Hagen, Donnerkuhle Quarry

8x6cm	© Harjo

FOV 1cm	© Harjo

FOV 0,6cm	© Harjo

FOV 12cm	© Harjo

Locality photo: 1

The Donnerkuhle quarry (operated by the Rheinkalk company, a subsidiary of the Lhoist consortium) is situated on the northern edge of the "Rheinisches Schiefergebirge" (Rhine Slate Mountains) in an area of Devonian Limestone (Massenkalk) . In the north-eastern part of the quarry a small zone of Schwarzschiefer (black slated Limestone) is situated in which discordant Calcite veins occur regularly. The Millerite is encountered in these discordant Calcite veins. Specimens have been found showing lath like Millerite crystals up to 10 cm in length (!) and cabinet specimens with lots of Millerite crystals ranging from 5 cm upwards were no rarity. Here one encounters the so called corkscrew Millerite, twisted Millerite crystals like the one linked in picture 2 above. Due to a fatal accident in another quarry of the Rheinkalk group there is now a ban on on-site collecting.
[Harjo Neutkens 2009]

Millerite
Germany
North Rhine-Westphalia, Sauerland, Meschede, Ramsbeck

4,6x4cm	© KrauklMinerals

4,6x4cm	© Peter Haas

Ancient lead and zinc mines located near the town of Ramsbeck delivered very nice Millerite.
We need someone to tell us about the specimens from this locality.

Millerite
Germany
North Rhine-Westphalia, Ruhr Coal Mining area, Recklinghausen, Marl-Hüls, Auguste-Victoria Mine

Scale 1 Inch, rule 1cm	©

3cm	© Peter Haas

Locality photo: 1

Ancient coal mine located at Marl-Hüls, around 7 km NW of Recklinghausen. Millerite was found in crystals up to 4 cm in length on splendid specimens, these have made Auguste-Victoria famous. [Bode, Wittern, Mineralien und Fundstellen BDR 1989]
Millerite was encountered in many of the Coal Mines in the Ruhrgebiet (Ruhr area), often in very good specimens.

Millerite
Germany
North Rhine-Westphalia, Ruhr Coal Mining area, Essen, Zollverein Mine

FOV 3cm	© Peter Haas

0,7cm	© jo-esche 2007

Coal Mine, closed in 1987. Many fine Millerite specimens were recovered from the mine during the time it was operated.
Millerite occurred in single crystals up to 10 cm in length as well as in star-like aggregates around Chalcopyrite crystals [Bode, Wittern, Mineralien und Fundstellen BDR 1989]

Millerite
Germany
Rhineland-Palatine, Siegerland, Wissen, Eichelhardt, Petersbach Mine

4.5cm	© Roger Lang 2003

Scale 1 Inch, rule 1cm	©

Located near Eichelhardt, about 7 km SSW of Wissen.
The iron and base metal ore deposit of the Petersbach mine belongs to the Siegerland-Wied siderite district. The mine was situated near the township of Eichelhardt approx. 7 km south of Wissen. First time mentioned in the 17th century, the early workings were on Pb and Ag ore. A significant period lasted 1780 to 1811 when mainly base metal ores were mined. Due to the exceptional suitability of the iron ore for the production of Spiegeleisen, a ferromanganese alloy containing up to 20 % manganese and small quantities of carbon and silicon, the mine was claimed again in 1823 (for "Stahlstein") and worked until 1890, when Spiegeleisen became more and more obsolete due to newly developed techniques in the production of iron and steel.
In the same year the mine was purchased by the Wissener Eisenhütten AG. At the turn of the century this company had to extended its ore basis and in 1901 a new shaft was sunk. During the 1930s the exhaustion of the ore reserves became more and more evident and finally in 1937 the mine was closed. Reaching a depth of 1025 m, the mine was one of the deepest ore mines in the Siegerland.
From 1780 to 1937 a total of 2.36 million tons of siderite ore, and from 1811 to 1937 4300 t of copper ore, 11540 t of Pb ore, 4830 t of Zinkblende (sphalerite) and 107 t of Ni ore were mined.
The mineralization is of hydrothermal vein type in devonian (meta-)sedimentary rocks (Upper to Lower Siegen) and consists of siderite veins with quartz gangue and base metal sulfide ores especially at the upper levels of the mine. Laspeyres describes "Antimonnickelglanz" (Ullmannite) and Millerite from the Petersbach mine in his 1893 article about Nickel mineral occurrences of the Rhineland and Westphalia region. The millerite finds were among the best of the Siegerland and crystals reached up to 8 cm lenght.
[Roger Lang 2009]

Millerite
Germany
Rhineland-Palatine, Siegerland, Wissen, Schönstein, Friedrich Mine

1,7x1,5 cm	© Rob Lavinsky

2,1x1,2 cm	© Rob Lavinsky

Info needed about specimens from this locality.

Millerite
Germany
North Rhine-Westphalia, Siegerland, Neunkirchen

Scale 1 Inch, rule 1cm	©

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

Millerite
Germany
North Rhine-Westphalia, Siegerland, Littfeld, Victoria Mine

Scale 1 Inch, rule 1cm	©

5.9x4.9cm	© Edward Minerals

Pb-Zn mine.
Mining started here in the 17th century, and was finally abandoned in 1927.
In 1909 Victoria Mine delivered the best Millerite crystals of the Siegerland. The shiny Millerites occurred in sprays and thick aggregates. [Bode, Wittern, Mineralien und Fundstellen BDR 1989]

Millerite
Germany
Rhineland -Palatine, Westerwald, Wied Iron Spar District, Neuwied, Puderbach, Reichensteinerberg Mine

Scale 1 Inch, rule 1cm	©

can someone help us with information about specimens from this locality?

Millerite
Germany
Bavaria, Franconia, Münchberg Metamorphic complex, Oberkotzau, Wurlitz, Hess quarry

FOV 3,5cm	© K.Gerl

A very beautiful as wel as interesting paragenesis is encountered in Wurlitz, Millerite together with Topazolite Garnet.
Many very nice specimens reside in German museums as well as in private collections.
The quarry lies in a Serpentinite body with inclusions of saussurite gabbro, worked intermittently since around 1880. The material was initially used as a gravel for railway construction, because its low contents of sodium, potassium and calcium are largely prohibiting any plant growth. Later on, it was used as a filling material for synthetic polymers.
Located west of Wurlitz and about 5 km ESE of Oberkotzau.

Millerite
Ireland
Co. Mayo, Sheeffry Mine (Tawnycrower Mine; Sheefry Mine; Sheffry Mine)

FOV 2,5cm	© Dr Stephen Moreton

FOV 2cm	© Dr Stephen Moreton

19th century trial for argentiferous galena. Consists of a series of small adits on a hillside.
Can anyone help us with information about specimens from this locality?

Millerite
Italy
Emilia-Romagna, Bologna Province, Gaggio Montano, Ca' dei Ladri (Silla)

FOV 0,3cm	© Chinellato Matteo

FOV 0,7cm	© Chinellato Matteo

Area in which occur cretaceous sedimentary rocks with hydrothermal veins that contain interesting minerals. The locality is not known for cabinet sized specimens but rather for outstanding micromounts.

Millerite
Netherlands
Limburg, Brunssum, Hendrik-Emma dumps

FOV 1cm	© Leon Hupperichs

FOV 0,5cm	© Leon Hupperichs

Dumps of the two former coal mines Hendrik and Emma. Nice Millerite has been found on the dumps comparable to those found in the Ruhr coal mining region just across the border in Germany and the Genk coal mining region nearby in Belgium.

Millerite
Norway
Telemark, Kragerø, Valberg Quarry

8cm	© Knut Eldjarn

A small find of excellent specimens with aggregates of millerite crystals to 3 cm was made in the Valberg quarry near the city of Kragerø in 1996 by Aslak Jensen. There is a large specimen on display at the Kongsberg mining museum and a few good specimens also exist in private collections in Norway.
[Knut Eldjarn 2009]

Millerite
Poland
Upper Silesia (Śląskie), Upper Silesian Coal Basin, Czerwionka-Leszczyny, Szczygłowice Mine

FOV 3cm	© Elek Szełęg

FOV 2cm	© Elek Szełęg

Dump of Szczygłowice Mine. Mineralization within sphaerosiderites (ankerite-dolomite series, barite, calcite-siderite series, marcasite, millerite, pyrite, quartz, sphalerite)
Can anyone help us with information about specimens from this locality?

Millerite
Spain
Catalonia, Tarragona, Priorat, Bellmint del Priorat, Eugenia Mine

2.5x2.1x3.3cm	© fabreminerals.com

7x5cm	© I. Gaspar 09

Site photo: 1, 2

The village of Bellmunt del Priorat was the center of one of the most prolific lead mining areas in Catalonia between the end of the 19th century and the 1970s.
The Eugenia Mine was the most important Pb mine in the area: it consisted of more than 14 km of galleries up to 620 m deep distributed in 20 levels, reaching more than 300 m below the sea level. A metallurgical ore-processing complex was built around the mine during the first years of the 20th century. A modernist syle building built in 1905, called "Casa de les Mines", hosted the "Minas del Priorato, S.A." company headquarters, laboratories and offices until the mine was definitely closed in 1972.

Millerite
United Kingdom
Wales, Rhonda-Cynon-Taff (Mid Glamorgan; Glamorgan, Coed Ely, Coed-Ely Colliery

crystals 1,5cm	© Ian Jones

FOV 3,5cm	© Peter Haas

Possibly the best known of the coalfield millerite locations, Coed Ely Colliery was opened in 1916 by The Welsh Navigation Steam Coal Co. Ltd. By 1938 there were 1,006 men employed.
Following reconstruction schemes in the 1950s & 60s, Coed Ely was linked underground and worked jointly with Cwm Colliery at Llantwit Fardre, over 5km to the east By the 1970's the collieries jointly produced 515,000 tons of steam coal a year with a workforce of 1,580 men.
Coed Ely Colliery closed in November 1986 and the site has since been landscaped.
Also other Collieries in the region provided nice Millerite specimens (for instance the Ferndale Pits)

Millerite
United Kingdom
Wales, Merthyr Tydfil (Mid Glamorgan; Glamorgan), Treharris, Deep Navigation Colliery

Spray 2,7cm	© Ian Jones

Spray 4,5cm	© ian jones

Originally named Harris's Navigation after the Harris Navigation Steam Coal Company's main shareholder (who also gave his name to the village of Treharris), shaft sinking began in 1873. At the time of their completion in 1878, the 760 yards deep south shaft was the deepest in the coalfield.
By 1896 the colliery was owned by Ocean Coal Co. Ltd and named Deep Navigation, at which time it employed 1,846 men and boys, rising to 2328 men at its peak in 1923.
For many years the the pit produced the best quality Welsh steam coal, during the 1980's average annual output reached 375,000 tons .
The Colliery produced high quality steam coal which was greatly in demand notably by Cunard Steamlines. Deep Navigation became the sole source of the coal used for the record-breaking "Blue Ribband" trans-Atlantic crossings of both the SS. Mauretania and the SS Lusitania.
Deep Navigation closed in 1991, the colliery buildings have been removed and the site extensively landscaped.
[Ian Jones 2009]

Millerite
United Kingdom
Wales, Rhondda-Cynon-Taff (Mid Glamorgan; Glamorgan), Tylorstown, Ferndale Pits (Blaenllechau Colliery)

Spray 2,5cm	© Ian Jones

Heavily overgrown dumps from Ferndale numbers 8 & 9 pits remaining. Sometimes referred to as Tylorstown tip or Llanwonno tip.
Historical note:
On Friday 8th of November 1867 the whole district of Ferndale was shaken by two consecutive explosions. 178 men and boys perished and a month had nearly past before all their remains had been recovered.
Just seventeen months later, on the 10th of June 1869, another explosion occurred at this fated colliery this time killing 53 men and boys.
Can you help us with more information about specimens from this locality?

Millerite
United Kingdom
Wales, Rhondda-Cynon-Taff (Mid Glamorgan; Glamorgan), Gelli, Gelli (Globe) Colliery

Spray 2x1,5cm	© Ian Jones

Main crystal 1,5cm	© Ian Jones

Originally sunk in 1870 by Thomas and Griffiths to reach the higher bituminous coal levels, further shafts were sunk to the steam coal levels in 1878. The mine was subsequently owned by Cory Brothers and Co, who held it until Nationalisation in 1947. By 1908 the workforce numbered 777 (steam coal pit) and 128 (house coal pit). The latter pit closed by 1945 and the steam coal pit in 1962. Large but very heavily overgrown tips still remain.

Millerite
United Kingdom
Wales, Caerphilly (Gwent, Monmouthshire), Markham, Markham Colliery

10 cm	© J.Ralph

FOV 6cm	©

Millerite from the south Wales Coalfield, United Kingdom

Coalfield millerite occurs as individual needles and sprays, typically 2-3mm generally within cavities in the ironstone, but also occasionally with the associated sandstone. Specimens over 10mm are considerably rarer, although individual crystals and radiating sprays to a maximum of about 50mm have been found.
When unaltered, millerite is a bright golden colour although many specimens show a degree of oxidation and are partly coated with, or altered to, a greenish-yellow mineral. Originally thought to be morenosite, work undertaken by The National Museum of Wales failed to confirm it's presence. Subsequent work by The University of Western Sydney has now confirmed the presence of nicklehexahydrite.
Well-terminated millerite crystals are extremely rare in the coalfield, as are those having abrupt directional changes. Curved crystals or those twisted into spirals (screw dislocations) are relatively common. Millerite has been found in direct association with all of the ironstone minerals with the exception of marcasite.
Millerite, the most well-known mineral from south-east Wales, was recorded from ironstones at Dowlais Ironworks in 1842 by W H Miller, sometime Professor of Mineralogy at Cambridge. Although previously known on the continent and named 'hair pyrites' or 'capillary pyrites', Miller added substantially to knowledge of the mineral and, in recognition, the name millerite was proposed by the German mineralogist Haidinger in 1845. Interestingly, the first record of Welsh millerite considerably predates Miller's description, a specimen of "hair pyrites" in a coalfield ironstone is illustrated in plate 287 (dated 1808), in Volume 3 of James Sowerby's famous series British Mineralogy.
Many older specimens in the National Museum of Wales and Natural History Museum (London) collections are labelled Merthyr Tydfil, although millerite is surprisingly rare in the area. Whilst millerite occurred here, the Spotted Vein at Dowlais was given as a location in 1861, it is probable that Merthyr, then the largest town in the area, is simply a generic locality for many early South Wales millerites occurring across the heads of the valleys from Ebbw Vale to Merthyr, and perhaps further afield.
[Ian Jones 2009]

Mineralogy, geology and mining history of the South Wales coalfield

The south Wales coalfield has a long history of mining for coal and for the associated ironstone, both were important to the overall development and economy of the area, the former until recent times. The coalfield has produced a comprehensive range of minerals. Most famous is millerite, which occurs in world class specimens, the type locality being Dowlais near Merthy Tydfil.
The coalfield runs across the counties of Monmouth, Glamorgan, Carmarthen and Pembroke forming, an elongated oval of carboniferous rocks extending from St Bride's Bay in the west to Pontypool in the east, a distance of some 90 miles. Its width varies from a maximum of about 16 miles across the main body of the coalfield in Glamorgan to about 4 miles in the much smaller detached part of the coalfield in Pembrokeshire.
Three types of coal occur: anthracite in the west, steam coal in the centre and north and bituminous coal around the southern and eastern rim. Although the coals grade together, they differ in terms of their volatile constituents and carbon content, the former increasing from anthracite to steam coal to bituminous coal, the latter decreasing. In total, 48% of the coalfield produced steam coal, 30% bituminous coal and 22% anthracite.
Many of the coalfield minerals, particularly the sulphides, occur in well-crystallised forms within cavities in ironstones found on the coaltips. Although widely distributed, it is possible to draw broad conclusions regarding their occurrence. Mineralisation in the ironstones, particularly sulphide mineralisation, is seen to be greatest in the centre and east of the coalfield where the most volatile-rich coals, the steam and bituminous coals occurred.
[Ian Jones 2009]

Millerite
United Kingdom
Cornwall, Callington District, Lezant, Greystones Quarry

Spray 1,9cm	© Ian Jones

A modern operation worked for roadstone, Greystone Quarry is situated on the strike of a lode system worked by several small 19th C lead mines(Greystone silver lead mine, Wh Sophia, North Tamar). The quarry cuts the eastern end of the vein system worked by the latter mine.

Millerite
United Kingdom
England, Co. Durham, North Pennines, Teesdale, Middleton-in-Teesdale, Colberry Mines, Coldberry Gutter

Scale 1 Inch, rule 1cm	©

Spray 1cm	© HW

Coldberry Gutter is the large hush at head of Hudeshope Beck. Fluorite, quartz, galena and sphalerite mineralisation is similar to that occurring at the adjacent Coldberry Mines complex, with the addition of a suite of minerals including millerite, quartz, siderite, galena sphalerite and calcite that occur within a bed of clay ironstones nodules found in an exposure at the top of the hush.

Millerite
USA
Iowa, Keokuk Co., Ollie, Kaser Quarry

5.7x4.1cm	© Rob Lavinsky

3x1,8x1,5cm	© Rob Lavinsky

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

Millerite
USA
Kentucky, Lincoln Co., Halls Gap, US 27 roadcut

4.6x3.9cm	© Rob Lavinsky

4x2,5x2cm	© 2004 John H. Betts

Locality photo: 1

Halls Gap is about 5 miles south of Stanford on US 27. This site is reopened as of 4/20/03 Hwy 27. Stanford is approx 30 miles west of I-75 at Mt. Vernon. Take Hwy 150 West to Stanford.
We need someone to tell us about the specimens from this locality.

Millerite
USA
Pennsylvania, Lancaster Co., Bart Township, Gap, Gap Mine (Gap Nickel Mine)

Scale 1 Inch, rule 1cm	©

4,5x3cm	© M.Heintzelman

An old nickel mine with millerite as the principal ore mineral. The Gap Nickel Mine was discovered in 1732, and was worked to some extent for copper, but was abandoned due to the small quantities present in the ore. In the early 1850's, it was discovered that the large ore vein contained a considerable quantity of nickel. Operated by the Gap Mining Co. until 1863, When Joseph Wharton, Founder of the Wharton School of Business at the University of Pennsylvania, took over ownership and operation of the mine.

Millerite
USA
Wisconsin, Milwaukee Co., Milwaukee, Eastbrook Park (Bertlett; North Milwaukee; Cementville; Lincoln Park; Capitol Drive; Washington Street Bridge; Humbolt Street Bridge)

Scale 1 Inch, rule 1cm	©

4.4x3.1cm	© Rob Lavinsky

Outcrops of dolostones and old quarries along Milwaukee River.
We need someone to tell us about the specimens from this locality.

Millerite
USA
Indiana, Monroe Co, Harrodsburg, SR 37 Roadcut

8x4,5x4,5cm	© Chris Tucker

FOV 6,5cm	© 2007 Peter Cristofono

Approx 109 km (67 miles) south of Indianapolis and 17 km (10.5 miles) north of Bedford. Just south of Monroe Lake / Harrodsburg exit, north of Bedford. On both sides of road. Geodes occur in the Harrodsburg Limestone, Middle Mississippian age strata.

Millerite
USA
Michigan, Huron Co., Pigeon, Wallace Stone Company Quarry (Wallace Quarry)

2,5x1,9x1,5cm	© Rob Lavinsky

1,2x1cm	© Rui Nunes 2006

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

Millerite
USA
New York, Jefferson Co., Antwerp, Sterling Mine

Scale 1 Inch, rule 1cm	©

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

Millerite
USA
Nevada, Elko Co., Bootstrap District, Meikle Mine

2.6x2.5x1.6cm	© Rob Lavinsky

5cm	©

Locality photos: 1, 2, 3, 4

Can you help us with information about specimens from this locality?

[Harjo Neutkens 2009]]]> Harjo Neutkens Best Minerals M Sun, 23 Aug 2009 18:03:23 +0000 http://www.mindat.org/forum.php?read,79,129405,129405#msg-129405 http://www.mindat.org/forum.php?read,79,129405,129405#msg-129405
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 M Wed, 18 Mar 2009 23:06:44 +0000