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Icosahedrite is the first known naturally occurring quasicrystal phase. It has the composition Al63Cu24Fe13 and is a mineral approved by the International Mineralogical Association in…

Ichnusaite is a very rarely found mineral. Ichnusaite is a natural compound of thorium and molybdenum with the formula Th(MoO4)2·3H2O. It was discovered in Su…

Ianbruceite is a rare hydrated zinc arsenate with the formula [Zn2(OH)(H2O)(AsO4)](H2O)2; material from the Driggith mine has traces of cobalt. It was first discovered at…

Hyalophane or jaloallofane is a crystalline mineral, part of the feldspar group of tectosilicates. It is considered a barium-rich potassium feldspar. Its chemical formula is…

Hypersthene is a common rock-forming inosilicate mineral belonging to the group of orthorhombic pyroxenes. It is relatively common mineral and is found in igneous and…

Hyalite is a form of opal with a glassy and clear appearance which may exhibit an internal play of colors if natural inclusions are present.…

Hiddenite is a pale-to-emerald green variety of spodumene that is sometimes used as a gemstone. It is a rare, transparent variety of spodumene, colored yellow-green…

Hessonite or “cinnamon stone” is a common variety of grossular with the general formula: Ca3Al2Si3O12. It is a calcium aluminum silicate. The name comes from…

The mineral aggregate heliotrope also known as bloodstone, is a variety of jasper or chalcedony. The “classic” bloodstone is green jasper (chalcedony) with red inclusions…

Hydrozincite, also known as zinc bloom or marionette, is a white carbonate mineral consisting of Zn5(CO3)2(OH)6. It is usually found in massive rather than crystalline…

Hatchettite (also mountain tallow, mineral tallow, mineral adipocire, or adipocerite) is a mineral hydrocarbon. It is a mineral paraffin wax C38H78 melting at 55° to…

Hydroxylapatite, also called hydroxyapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH) but is usually written Ca10(PO4)6(OH)2 to denote…