HETEROGENITE
HETEROGENITE Heterogenite – CoO(OH) – is a relatively rare hydroxide that occurs as a secondary mineral in some Co deposits. Due to the volumes in which it is sometimes found, it can be an important cobalt ore. Macroscopically, it closely resembles psilomelane. An older term for heterogenite is “stainerite” (or “stainierite”). According to more recent […]
HEWETTITE
HEWETTITE Hewettite – CaV6O16·9H2O – is an extremely rare oxide and vanadate, typically occurring as a secondary mineral. It serves as a secondary vanadium ore mineral, as it contains 71.43% V₂O₅. It is somewhat soluble in water and is neither fluorescent nor magnetic. Dehydration of hewettite yields the mineral metahewettite; both are classified within the […]
HESSITE
HESSITE Hessite – Ag2Te – is a relatively rare sulfide that serves as a silver ore, as it contains 63.3% Ag. It contains Au and Pb as impurities. At temperatures above 155°C, hessite is cubic; as the temperature drops, it develops fine phase-transformation lamellae. Macroscopically, the crystals may resemble cubes or thin orthorhombic crystals, some […]
HEAZLEWOODITE
HEAZLEWOODITE Heazlewoodite – Ni3S2 – is a rare sulfide found in serpentinized dunites. It does not constitute an ore. 1. Characteristics Crystal system: Trigonal trapezohedral. Color: Light bronze to brass-yellow. Habit: Massive, fine-grained. Small, rare crystals; tabular or pseudo-cubic rhombohedral. Cleavage: No. Tenacity: Brittle? Twinning: Possible. Fracture: Unequal. Mohs Hardness: 4 Parting: […]
HYDROZINCITE
HYDROZINCITE Hydrozincite – Zn5(CO3)2(OH)6 – is a common carbonate mineral that occurs primarily in the oxidation zones of zinc ores. It constitutes a minor zinc ore. “Calamine” is a mining term applied to a mixture of hydrozincite, smithsonite, and hemimorphite. It may contain Fe and Cu and forms pseudomorphs after dolomite. It exhibits intense blue […]
HARMOTOME
HARMOTOME Harmotome – (Ba,Ca,K,Na)5[Al5Si11O32].12H2O – is a tectosilicate belonging to the Zeolite Group and the Phillipsite Subgroup. It is a relatively rare mineral, characteristic of certain basic rock types. It holds no significance as an ore, serving primarily as a collector’s mineral. There is a variety known as morvenite, which exhibits a fusiform habit formed by […]
HEMIMORPHITE
HEMIMORPHITE Hemimorphite – Zn4Si2O7(OH)2·H2O – is a relatively common sorosilicate, characteristic of oxidation zones of Zn sulfide ores. It makes up, along with smithsonite and hydrozincite, the Zn ore called “calamine” by the mining industry. The name hemimorphite derives from the fact that the mineral crystallizes in the orthorhombic pyramidal class, forming crystals with a […]
HOLLANDITE
HOLLANDITE Hollandite – Ba(Mn4+6,Mn3+2)O16 – is a relatively common oxide that is part of some Mn ores. In 2012, the IMA revised the nomenclature of the Hollandite Supergroup. Now hollandite is redefined as the Ba-Mn3+ end of the Coronadite Group. Classical hollandite was redefined as ferrihollandite, a name that designates the Ba-Fe3+ end of the […]
HOLMQUISTITE
HOLMQUISTITE Holmquistite – {Li2}{Mg3Al2}(Si8O22)(OH)2 – is a very rare amphibole that occurs associated with lithium-bearing pegmatites. It does not form ore, but it serves as a guide in the identification of lithium-bearing pegmatites (see London, D. 1986, Holmquistite as a Guide to Pegmatitic Rare Metal Deposits. Economic Geology, v. 81, p. 704-712). The Holmquistite Group […]
HOPEITE
HOPEITE Hopeite – Zn3(PO4)2·4H2O – is a rare phosphate that occurs in some very specific geological environments. It is part of Zn ores, but is never the main ore mineral in the deposit. It is classified in the Hopeite Group and is the phosphate analog of arsenohopeite. It has two varieties, α-hopeite and β-hopeite. It […]