ALABANDITE
ALABANDITE Alabandite – MnS – is a relatively rare sulfide, with 63.14% Mn. It is associated with Mn deposits and polymetallic sulfide deposits. It is classified in the Galena Group and is polimorph with browneite and with rambergite. It frequently contains appreciable levels of FeS. It may also contain Mg and Co. 1. Characteristics Crystal […]
ALTAITE
ALTAITE Altaite – PbTe – is a relatively rare sulfide. Due to this rarity, it does not have great economic importance, despite Te being a strategic semi-metal with many uses, especially in the construction of photovoltaic panels. There are only three deposits on the planet where Te is obtained as a primary ore; most Te […]
AMBLYGONITE
AMBLYGONITE Amblygonite – (Li,Na)AlPO4(F,OH) – is a fairly rare phosphate that occurs mainly in pegmatites rich in Li and PO4. It constitutes an important Li ore, included in the “hard rock lithium ore” type minerals, in contrast to Li extracted from salt flat brines. Amblygonite (more F than OH) forms a series with montebrasite (more […]
ANGLESITE
ANGLESITE Anglesite – PbSO4 -is an uncommon sulfate, but it is the most common secondary lead mineral along with cerussite. It contains 74% lead, but only constitutes ore when it occurs in larger volumes. It has sporadic uses as a gemstone. It is classified in the Barite Group and forms a series with barite. It […]
ASBOLANE
ASBOLANE Asbolane – (Ni,Co)2-xMn4+(O,OH)4·nH2O – is a rarer (or less detected!) hydroxide, forming part of Mn ores and mainly Co (up to 32%) and Ni. It is known as “nickel-bearing wad”. It is one of the many Mn minerals that, for centuries, have been sheltered under the “umbrella” terms “cryptomelane”, “psilomelane” and “wad”. These terms […]
ARSENIC
ARSENIC Arsenic – As – is a relatively rare native element. It is not an ore, as arsenic is recovered from arsenopyrite present in ores of other metallic elements. It is classified in the Arsenic Group, forms a series with Sb, and is dimorphic with arsenolamprite (orthorhombic As). It always contains some Sb; it may […]
AESCHYNITE
AESCHYNITE Aeschynite is a fairly rare oxide, typical of some granitic pegmatites. It is an ore of Rare Earth Elements (REEs). “Aeschynite” actually refers to a group of oxides containing REEs, the most common member of the group being that with yttrium. The Aeschynites Group is made up of: Aeschynite-(Ce) – (Ce,Ca,Fe)(Ti,Nb)2(O,OH)6 Nioboaeschynite-(Ce) – (Ce,Ca)(Nb,Ti)2(O,OH)6, Aeschynite-(Y) […]
ANORTHOCLASE
ANORTHOCLASE Anorthoclase is a relatively abundant tectosilicate of the Feldspar Group, characteristic of alkaline volcanic rocks. It has no economic importance. Anorthoclase is no longer considered a mineral species, as it is merely an intermediate member in a binary solid solution, an intermediate feldspar between sanidine (rich in K, “low sanidine”) and albite (rich in […]
ARFVEDSONITE
ARFVEDSONITE Arfvedsonite – [Na] [Na2] [Fe2+4Fe3+] Si8O22(OH)2 – is an inosilicate, a sodium amphibole, quite rare, typical of rare alkaline rocks. It has no economic use; it is found on the market only as a mineral for collectors. “Arfvedsonite” is not actually a mineral, but just a generic term used to designate the Arfvedsonite Group’s […]
ARAGONITE
ARAGONITE Aragonite – CaCO3 – is a fairly common carbonate, but much rarer than calcite, the most common polymorph of Ca carbonate; the third is vaterite (very rare). It does not constitute ore, but aesthetic pieces fetch a competitive price in the collector minerals market. It is the main member of the Aragonite Group. May […]