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 […]
COLUMBITE
COLUMBITE Columbite – (Mg,Fe++,Mn)(Nb,Ta)2O6 – is a rare oxide. It is the most common Nb ore, as well as being a Ta ore. “Columbite”, by the current classification, is no longer a mineral species, but only a generic term used for members of the Columbite Group, composed of the Columbite-(Fe)-Tantalite-(Fe) Series and the Columbite-(Fe)-Columbite-(Mn) Series. […]
CORONADITE
CORONADITE Coronadite – Pb(Mn4+6Mn3+2)O16 – is a common manganese oxide, but rarer than other Mn oxides. It is a minor component of Mn ores. It is classified in the Coronadite Group, in the Hollandite Supergroup. It may contain Al, Fe, and H2O. Conclusive identification of many Mn oxides is obtained only or preferably with X-ray […]
CRIPTOMELANE
CRIPTOMELANE Cryptomelane – K(Mn4+,Mn2+)8O16 – is a common oxide, the most common mineral in those very fine-grained Mn oxide masses formerly generically called “psilomelane.” It is difficult to recognize, so much so that its name means “the hidden dark one” (Greek: kryptos = hidden, melano = dark). It was proposed only in 1942 and approved in […]
CHRYSOCOLLA
CHRYSOCOLLA Chrysocolla – (Cu,Al)2H2Si2O5(OH)4·nH2O (?) – a phyllosilicate, is one of the many minerals that form from the alteration of copper sulfides in oxidation zones. Locally, it is still a minor copper ore, but historically it was very important as a copper ore. It is used as a minor gemstone due to its low hardness. […]
CORUNDUM
CORUNDUM Corundum – Al2O3 – is a rare oxide that occurs in some aluminum-rich rocks. It is important as a gemstone, as an abrasive, and as a refractory. It is classified in the Hematite Group and may contain Ti, V, Fe, and Cr. Corundum has always been a material of high economic interest, and there […]
COBALTITE
COBALTITE Cobaltite – CoAsS – is a rarer sulfide, characteristic of high-temperature hydrothermal veins. In addition to its historical uses as a pigment, cobalt is now a strategic industrial metal. Cobaltite can contain Ni, Cu, Pb, and Sb. There are two varieties (with Fe, with Pd). It forms a series with gersdorffite (NiAsS). When heated, […]
CHABAZITE
CHABAZITE Chabazite – (Ca,K2,Na2)2[Al2Si4O12]2.12H2O – is a tectosilicate from the Zeolite Group. Typically occurs as a secondary mineral in vesicles and fractures of volcanic rocks and is uncommon, it is one of the rarest zeolites. It has no economic importance. “Chabazite” is actually not a mineral, but just a generic term used for members of […]
CHALCOSTIBITE
CHALCOSTIBITE Chalcostibite – CuSbS2 – is a rather rare sulfosalt, typically found as an early-stage mineral in hydrothermal Sb-Cu-Pb-Ag veins. It occurs in polymetallic ores—predominantly those containing antimony—but is never the primary ore mineral of the deposit. It is classified within the Chalcostibite Group and is the sulfur analogue of pribramite (the selenium analogue). It […]
COLUSITE
COLUSITE Colusite – Cu13VAs3S16 – is a very rare sulfosalt, though likely far more common than it appears. When it does occur, it is always present in small quantities. It does not constitute an ore and can be classified as one of the “fahlore” minerals (complexly composed, dark-colored ores). It belongs to the Germanite group […]