AUGITE-(Ti)
AUGITE-(Ti) Augite-(Ti) or “titanian augite” ou “titanaugite” – (Ca,Na)(Mg,Ti, Fe,Al,)(Si,Al)2O6 – is a variety of augite rich in Ti, containing more than 3 wt% TiO2 – reaching as much as 6 wt%. This stands in stark contrast to common augites, which contain only between 0.5 and 0.8 wt% TiO2. It is not a distinct mineral […]
ATACAMITE
ATACAMITE Atacamite – Cu2Cl(OH)3 – is a relatively rare halide, characteristic of Cu deposits formed under arid and saline conditions, in the absence of associated carbonates. It serves as an important copper ore and can be the primary ore mineral within a deposit. It is classified within the Atacamite Group and is polymorphous with botallackite, […]
ANTLERITE
ANTLERITE Antlerite – Cu3(SO4)(OH)4 – is a relatively common sulfate and a primary ore mineral in some large porphyry copper deposits, as it contains 67.27% CuO. Antlerite typically occurs as vein fillings, consisting of fibrous crystals oriented perpendicular to the direction of the vein. The thickness of these veins ranges from less than a millimeter […]
ARROJADITE
ARROJADITE Arrojadites -KNa4CaMn++4Fe++10Al(PO4)12(OH,F)2 – are very rare phosphates typical of granitic pegmatites. Due to their rarity, they are not considered ore, despite containing 40% P2O5 . “Arrojadite” is not actually a single mineral; it is a group subdivided into four subgroups, comprising a total of 16 mineral species. The most common is arrojadite-(KFe). The group, […]
AURICHALCITE
AURICHALCITE Aurichalcite – (ZnCu)5(CO3)2(OH)6 – is a carbonate typical of the oxidation zones of Cu and Zn deposits, being one of the many secondary copper ore minerals found in oxidized ores. The mineral never forms large crystals; it always occurs as thin coatings, thick crusts, or divergent tufts of small, fragile acicular crystals that can […]
ANKERITE
ANKERITE Ankerite – Ca(Fe2,Mg,Mn2+,)(CO3)2 – is a relatively rare carbonate mineral. It does not constitute an ore. It is classified within the dolomite group, and its composition is very similar to that of dolomite, though with the substitution of Mg by varying amounts of Fe and Mn. It forms a solid-solution series with dolomite and […]
AWARUITE
AWARUITE Awaruite – Ni3Fe – is a rare alloy. It generally does not constitute an ore; however, a low-grade awaruite deposit is currently being developed in British Columbia (Canada), with the awaruite disseminated within an ultramafic/ophiolitic complex. It may contain Cu, Co, S, P, and Si. There is an Ir-bearing variety. An important characteristic of […]
ANDORITE
ANDORITE Andorite – PbAgSb3S6 – is a rather rare sulfosalt characteristic of hydrothermal veins. It is generally a secondary ore but can occur in economically significant volumes, such as in certain deposits in the Andes. Andorite crystals are actually polycrystals composed of “andorite-IV” and “andorite-VI.” Andorite may contain Cu, Fe, and Zn. 1. Characteristics Crystal […]
ANILITE
ANILITE Anilite – Cu7S4 – is one of the forms of copper sulfide. It is relatively rare and occurs in copper ores. There are nine different minerals composed solely of Cu and S. The copper sulfide formed at low temperatures (T < ~105°C) is monoclinic chalcocite. At high temperatures (T > ~105°C) -including in blast […]
ASTROPHYLLITE
ASTROPHYLLITE Astrophyllite – K2NaFe2+7Ti2Si8O26(OH)4F – is a fairly rare inosilicate, typical of some lithotypes of extreme composition. It is not an ore, but collector’s pieces fetch high prices. It belongs to the Astrophyllite Group and forms a series with kupletskite. It may contain various impurities such as Nb, Ta, Zr, Al, Mg, Mn and Ca. […]