This article has been prepared for the Mindat Best Minerals project. The aim of this project is to present information on important localities and specimens for each mineral specie. As new finds are made and new knowledge is made available the individual articles will be revised to include this information. Readers are encouraged to contribute by posting a response in this thread. All revisions will be stored, thus ensuring traceability and availability of previously included information. A complete list of articles can be found in the list of finished Best Minerals articles. To cite this version: Currier, R. (2010): Cronstedtite. revision 1.0. Mindat Best Minerals Project, article "mesg-69-166186". Please be advised that the photos cannot be used without the consent of the copyright holder
Cronstedtite
Cronstedtite is not a common mineral but it is not extremely rare and Mindat lists 37 localities (2010). It was recognized as a species since about 1890. By far the best locality for specimens appears to be the Herja mine in Romania. Many of the fine specimens from this mine have suffered disintegration of their sulfide matrix and large specimens (larger than 5cm0 are very rare because they have mostly fallen apart. The mineral itself appears to be stable.
Cronstedtite,
Bolivia,
Potosí Department, Rafael Bustillo Province, Llallagua, Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi)
Cronstedtite,
France,
Languedoc-Roussillon, Carcassonne, Aude, Mas-Cabardès, Salsigne, Salsigne mine
Cronstedtite,
Germany,
Saxony-Anhalt, Harz Mts, Gernrode
Cronstedtite,
Peru,
Huánuco Department, Dos de Mayo Province, Huallanca District, Huanzala Mine
The mineral is rather rare at Huanzala. Of about 20 trips made to Peru to buy minerals I saw only one good specimen of about 15cm. The Cronstedtites were growing thickly crusted on a matrix of pyrite crystals and looked similar to the material from Romania pictured below, but a bit blacker. For a while it was probably the best specimen of Cronstedtite produced in the southern hemisphere, but the pyrite eventually disintegrated and only a few TN and micro specimens remain now. Ill try and get a picture of them to post here.
Cronstedtite,
Romania,
Maramures Co., Baia Mare (Nagybánya)
Cronstedtite,
Romania,
Maramures Co., Baia Mare (Nagybánya), Herja Mine (Kisbánya)
The mine is near the village of Chuizbaia. Kisbánya was the old Hungarian name for this village. The Cronstedtites from this old locality have yet no rivals. The look almost black but are really almost an dark azurite blue. They are frequently found growing on little brown bladed siderite crystals which is typical if not unique for this locality. The specimens from this locality are usually found growing on a sulfide matrix that over time has proven to be not stable and most of the great specimens from this locality have fallen apart. Specimens over 5cm are quite rare. I know of only two great ones in the United States and one of those may have disintegrated. Martin Stevko comments: "I saw this specimen from Philadelphia Academy of Scieneces presonally and I remeber that it was superb. Also I have personal experience with cronstedtite decomposing. Also specimens from Herja tend to by unstable, because matrix of these specimens usually contain pyrite. I saw in old collections also cronstedtites from other localities (Kutná Hora, Příbram) a these are also unstable. In the Los Angeles area I only knew of one nice small Cronstedtite from this locality, but over the years it also fell apart.
Cronstedtite,
Spain,
Murcia, Sierra de Cartagena, La Unión, Brunita Mine
Cronstedite,
United Kingdom,
England, Cornwall, Camborne - Redruth - St Day District, Gwennap area, Wheal Jane, Baldhu
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Cronstedtite
Fe2+2Fe3+<(Si,Fe3+)2O5>(OH)4
trigonal
Cronstedtite is not a common mineral but it is not extremely rare and Mindat lists 37 localities (2010). It was recognized as a species since about 1890. By far the best locality for specimens appears to be the Herja mine in Romania. Many of the fine specimens from this mine have suffered disintegration of their sulfide matrix and large specimens (larger than 5cm0 are very rare because they have mostly fallen apart. The mineral itself appears to be stable.
Cronstedtite,
Bolivia,
Potosí Department, Rafael Bustillo Province, Llallagua, Siglo Veinte Mine (Siglo XX Mine; Llallagua Mine; Catavi)
Cronstedtite,
France,
Languedoc-Roussillon, Carcassonne, Aude, Mas-Cabardès, Salsigne, Salsigne mine
Cronstedtite,
Germany,
Saxony-Anhalt, Harz Mts, Gernrode
Cronstedtite,
Peru,
Huánuco Department, Dos de Mayo Province, Huallanca District, Huanzala Mine
The mineral is rather rare at Huanzala. Of about 20 trips made to Peru to buy minerals I saw only one good specimen of about 15cm. The Cronstedtites were growing thickly crusted on a matrix of pyrite crystals and looked similar to the material from Romania pictured below, but a bit blacker. For a while it was probably the best specimen of Cronstedtite produced in the southern hemisphere, but the pyrite eventually disintegrated and only a few TN and micro specimens remain now. Ill try and get a picture of them to post here.
Cronstedtite,
Romania,
Maramures Co., Baia Mare (Nagybánya)
Cronstedtite,
Romania,
Maramures Co., Baia Mare (Nagybánya), Herja Mine (Kisbánya)
The mine is near the village of Chuizbaia. Kisbánya was the old Hungarian name for this village. The Cronstedtites from this old locality have yet no rivals. The look almost black but are really almost an dark azurite blue. They are frequently found growing on little brown bladed siderite crystals which is typical if not unique for this locality. The specimens from this locality are usually found growing on a sulfide matrix that over time has proven to be not stable and most of the great specimens from this locality have fallen apart. Specimens over 5cm are quite rare. I know of only two great ones in the United States and one of those may have disintegrated. Martin Stevko comments: "I saw this specimen from Philadelphia Academy of Scieneces presonally and I remeber that it was superb. Also I have personal experience with cronstedtite decomposing. Also specimens from Herja tend to by unstable, because matrix of these specimens usually contain pyrite. I saw in old collections also cronstedtites from other localities (Kutná Hora, Příbram) a these are also unstable. In the Los Angeles area I only knew of one nice small Cronstedtite from this locality, but over the years it also fell apart.
Cronstedtite,
Spain,
Murcia, Sierra de Cartagena, La Unión, Brunita Mine
Cronstedite,
United Kingdom,
England, Cornwall, Camborne - Redruth - St Day District, Gwennap area, Wheal Jane, Baldhu
RevisionHistory
Revision no date description editor1.02010 First Draft Rock CurrierClick here to view Best Minerals C and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.
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