CYLINDRITE
CYLINDRITE Cylindrite – Pb3Sn4FeSb2S14 – is an extremely rare sulfosalt found in hydrothermal Sn-Ag veins. The type locality for cylindrite are the Santa Cruz and Trinacria mines (Poopó, Oruro, Bolivia). It is classified within the Cylindrite Group. Its composition is variable; silver (Ag) is a common impurity. 1. Characteristics Crystal system: Triclinic pinacoidal. […]
CATTIERITE
CATTIERITE Cattierite – CoS2 – is a very rare sulfide and, consequently, of no importance as an ore. It is classified within the Pyrite Group, forming a series with pyrite and another with vaesite (NiS2). Thus, it may contain varying amounts of Fe and Ni, as well as Cu. 1. Characteristics Crystal system: Cubic diploidal. […]
CONNELLITE
CONNELLITE Connellite – Cu19(SO4)(OH)32Cl4·3H2O – is a very rare sulfate found in the oxidation zones of copper ores. It is classified within the Connellite-Buttgenbachite Series and is isostructural with buttgenbachite. 1. Characteristics Crystal system: Hexagonal dipyramidal ditrigonal. Color: Blue to blue-green. Habit: Elongated prismatic, acicular, in divergent radial tufts, fibrous, crusts […]
CELESTINE
CELESTINE Celestine – SrSO4 – is a relatively rare sulfate, yet it is the most common strontium (Sr) mineral and the primary ore mineral for strontium. It is classified within the Barite Group, with which it forms a series (a complete solid solution). It forms a limited solid solution with anhydrite. It may contain Ca […]
CRICHTONITE
CRICHTONITE The mineral currently designated as “crichtonite” – Sr(Mn,Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH)38 – is a very rare oxide of no economic importance. It belongs to the Crichtonite Group, which comprises 17 other members. It forms a series with senaite. It is radioactive and is macroscopically very similar to ilmenite. In the past, the name “crichtonite” was applied to […]
COHENITE
COHENITE Cohenite – Fe3C – is a native element that occurs abundantly in meteorites but is found on Earth only in specific geological settings. It has no economic use. It is strongly magnetic, a property that does not aid in its identification because native iron – with which it is associated – is also magnetic. […]
CHRYSOBERYL
CHRYSOBERYL Chrysoberyl – BeAl2O4 – is a fairly rare oxide, characteristic of some granitic pegmatites. It can be a Be ore. As a collector’s mineral and as a gemstone, it can reach very high prices. A chromiferous, gemological variety is alexandrite, which is trichroic. It has a dark yellow-green to bluish-green color in sunlight, but […]
COFFINITE
COFFINITE Coffinite – U(SiO4).nH2O – is a relatively rare nesosilicate. It is a uranium ore, common in the Western USA. It is classified in the Zircon Group, in the Zircon-Thoriogummite Series. It may contain, as impurities, Fe, As, Pb, V, and Al. There is a variety with up to 13.8% ZrO2 and up to 3.4% […]
CHALCOPHANITE
CHALCOPHANITE Chalcophanite – ZnMn4+3O7 · 3H2O – is a fairly rare oxide associated with Zn and Mn ores. It is classified in the Chalcophanite Group and may contain Fe and/or Mn replacing Zn. When it occurs with a pseudo-octahedral habit, it can be confused with heterolite, with which it is frequently associated. It is almost […]
COLEMANITE
COLEMANITE Colemanite – Ca[B3O4(OH)3].H2O – is a very rare borate, characteristic of evaporitic sequences. It integrates B ores with other B minerals. It was the most important B ore until the discovery of kernite in 1926. Some colemanites from Turkey exhibit luminous pale yellow or pale green fluorescence due to the presence of As. Other […]