Olivenite

General Information: Chemical Formula:Cu2AsO4(OH) Composition:(Molecular Weight = 283.02 gm)Copper 44.91 % CuArsenic 26.47 % AsHydrogen 0.36 % H Oxygen 28.27 % O  Empirical Formula: Cu2(AsO4)(OH) Name Origin:From the German olivernerz, literally "olive" ore, in allusion to its typical color.Physical Properties: Cleavage:[110] Indistinct, [010] Indistinct, [110] Indistinct Color:olive green, yellowish brown, dirty white, blackish green, or liver brown. Density:4.1 - 4.4, Average = 4.25 Diaphaniety:Subtransparent to translucent to opaque Habits:Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Reniform - "Kidney like" i n shape (e.g.. hematite). Hardness:3 - Calcite Luminescence:None. Luster:Vitreous - Greasy Streak:yellowish greenMore details...