Legrandite

arsenate

keyword 4

Formula: Zn2(AsO4)(OH).H2O
Hydrated arsenate containing hydroxyl
Specific gravity: 3.98 to 4.01
Hardness: 4½
Streak: White
Colour: Yellow to colourless; pale yellow to colourless in transmitted light.
Environments

Pegmatites rarely
Hydrothermal environments

Legrandite is an uncommon secondary mineral occurring in the oxidised zones of arsenic- and zinc-bearing deposits, and, rarely, in granite pegmatites (Mindat, Webmin, HOM). Common associates include adamite, limonite, paradamite, scorodite and smithsonite (Mindat).

At the Ojuela mine, Durango, Mexico, legrandite is associated with adamite, paradamite, köttigite, scorodite and smithsonite (HOM).

At the type locality, Flor de Peña Mine, Nuevo Leon, Mexico, legrandite occurs in the oxidised zone of an arsenic-bearing zinc deposit, associated with pyrite, and with siderite and mimetite on massive sphalerite (Dana, Mindat).

At Tsumeb, Namibia, legrandite is associated with leiteite, smithsonite and reinerite (HOM).

At Sterling Hill, New Jersey, USA, legrandite is associated with köttigite, adamite, pharmacosiderite and scorodite (HOM).

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