CALAVERITE
CALAVERITE Calaverite – AuTe2 – is a rarer telluride, one of the few Au ores besides native gold. Moreover, it is the most common Au mineral after native gold. It was the mineral of the Western Australian gold rushes in the 1890s, where it was initially mistaken for pyrite and used as a building and […]
CROCOITE
CROCOITE Crocoite – PbCrO4 – is a very rare chromate, formed under very special conditions. It can be a Cr ore and has been used for paints, but in the collector’s mineral market it fetches very high prices. Exceptional collector’s pieces come from Dundas Mine and Adelaide Mine (Dundas, Tasmania). It may contain Zn and […]
CHALCANTHITE
CHALCANTHITE Chalcanthite – CuSO4.5H2O – is a relatively common sulfate, one of several secondary copper minerals. It is part of oxidized copper ores in arid climates, but only rarely is or has been the main ore mineral of the deposit. It has some demand as a collector’s mineral, but needs to be stored in compatible […]
CARNALLITE
CARNALLITE Carnallite – KMgCl3.6H2O – is a less frequent halide that occurs in evaporitic sequences and is very important as a K ore (for fertilizers!); only sylvite (KCl) is more important. Locally, carnallite is mined as a source of Mg. It is inconspicuous, rarely forming crystals. The mixture of carnallite with halite is called “almeraite”. […]
CRYOLITE
CRYOLITE Cryolite – Na3[AlF6] – is a very rare halide that was historically used as an Al ore and later as a flux in the electrolytic processing of bauxite, the main Al ore. It was mined for over a century from an occurrence in Ivigtut, Greenland. The world’s largest reserve, of more than 9 million […]
COLORADOITE
COLORADOITE Coloradoite – HgTe – is a very rare telluride, which is part of polymetallic ores containing Au, Ag, and Hg. It belongs to the Sphalerite Group and contains 61.12% Hg and 38.88% Te. It may contain Pb. Special care is needed when grinding and polishing coloradoite due to the presence of mercury, which is […]
CARROLLITE
CARROLLITE Carrollite – CuCo2S4 – is a very rare sulfide that occurs in cobalt ores. It usually contains Ni. It is classified in the Carrollite Subgroup, in the Thiospinel Group, of the Spinel Supergroup, being isostructural with linnaeite. 1. Characteristics Crystal system: Cubic hexaoctahedral. Color: Bright silver color. Rarely tarnishes to copper red or violet […]
CLAUSTHALITE
CLAUSTHALITE Clausthalite – PbSe – is a rarer selenide. It is not an ore, despite being the most common Se mineral. Se is obtained from sulfide ore minerals of many different metals, as Se often replaces a small percentage of S there. Clausthalite belongs to the Galena Group and is classified in the Clausthalite-Galena Series. […]
CHLORARGYRITE
CHLORARGYRITE Chlorargyrite – AgCl – is a relatively rare halide that occurs associated with Ag ores. It constitutes an Ag ore. Chlorargyrite is dimorphic with bromargyrite, with which it forms a solid solution. It may contain small amounts of Hg and Na. Like all silver minerals, it changes color once exposed to light, usually darkening. […]
CHONDRODITE
CHONDRODITE Chondrodite – Mg5(SiO4)2F2 – is a fairly rare nesosilicate, characteristic of skarns and carbonatites. It has no economic importance.It is classified in the Humite Group, is dimorphic to ribbeite, and may contain Ti, Al, and Mn. There is a variety containing a higher Ti content, titanochondrodite. It can be macroscopically confused with clinohumite. 1. Characteristics […]