Chemical Formula: Zn2(AsO4)(OH)·H2O
Locality: Ojuela mine near Mapimi, Durango.
Name Origin: Named after the Belgian mining engineer, Legrande.
Legrandite is a rare zinc arsenate mineral, Zn2(AsO4)(OH)·H2O.
It is an uncommon secondary mineral in the oxidized zone of arsenic bearing zinc deposits and occurs rarely in granite pegmatite. Associated minerals include: adamite, paradamite, kottigite, scorodite, smithsonite, leiteite, renierite, pharmacosiderite, aurichalcite, siderite, goethite and pyrite. It has been reported from Tsumeb, Namibia; the Ojuela mine in Durango, Mexico and at Sterling Hill, New Jersey, USA.
It was first described in 1934 for an occurrence in the Flor de Peña Mine, Nuevo Leon, Mexico and named after M. Legrand, a Belgian mining engineer .
Town of Origin : MINE FLOR DE PENA, LAMPAZOS, NUOVA LEON
Country of Origin : MEXIQUE
Refractive Index: from 1,67 to 1,74
Axial angle 2V: 50°
Color: Yellow, Yellowish orange.
Fracture: Brittle – Conchoidal – Very brittle fracture producing small, conchoidal fragments.
Hardness: 4-5 – Fluorite-Apatite
Luster: Vitreous (Glassy)