Adamite

Formula: Zn2(AsO4)(OH)

Name: After G.J.Adam, a french mineralogist who owned in his collection the first specimens which have been studied in 1866. It is a secondary mineral found in oxidation zones from zinc deposits containing arsenic-bearing minerals. In terms of chemistry, but not structure, adamite in an arsenic equivalent (stoichiometrically similar to) of tarbuttite. The two minerals are not analogous. Adamite forms a solid solution with the copper arsenate Olivenite, and the intermediate, structurally distinct member Zincolivenite.

Type Locality: Chanarcillo, Chile and Cap Garonne, Toulon, France

Color: The variety of colors is surprising: white, colourless, frequently pale yellow, honey-yellow, brownish yellow, rose red; blue, pale green to green, may be zoned; bright green (Cu-bearing); bright pink, purple (Co-bearing, Mn-bearing)

Lustre: Vitreous, Sub-Vitreous, Waxy, Greasy

Hardness: 3.5

Density: 4.4

Crystal System: Orthorhombic

Member of: Olivenite Group