Legrandite
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Legrandite | |
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Yellow radiating prismatic crystals on limonite
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General | |
Category | Mineral |
Chemical formula | Zn2(AsO4)(OH)·(H2O) |
Identification | |
Color | Yellow or yellowish orange to colourless |
Crystal habit | Crystalline, prismatic |
Crystal system | Monoclinic |
Cleavage | Imperfect, poor in one direction |
Fracture | Brittle, conchoidal |
Mohs Scale hardness | 4.5-5 |
Refractive index | 1.675-1.74 |
Streak | White |
Specific gravity | 4.0 |
Legrandite is a rare arsenate mineral, discovered in 1934 and named after the Belgian mining engineer Legrand. Chemically, it is a hydrated zinc arsenate hydroxide, found as a secondary mineral in zinc ores, often in association with limonite. The most notable source of the mineral is the now abandoned Ojuela mine in Durango, Mexico. It is highly praised for its vitreous rich yellow colour and is a desirable item among mineral collectors.