General Information:
Chemical Formula:Cu++2As+++++2O7·3(H2O)
Composition:(Molecular Weight = 442.98 gm)Copper 28.69 %
CuArsenic 33.83 %
AsHydrogen 1.37 %
H Oxygen 36.12 %
O Empirical Formula: Cu2As2O7·3(H2O)
Environment:Coatings on quartz.
IMA Status:Approved IMA
Locality:Cap Garonne mine, Var, France.
Name Origin:Named from the Latin gemini, twins, in allusion to the usual character of the crystals.
Physical Properties: Cleavage:[001] Perfect
Color:light green or sea green.
Density:3.7 - 3.71, Average = 3.7
Diaphaniety:Transparent
Habits:Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite), Columnar - Forms columns, Twinning Common - Crystals are usually twinned.
Hardness:3-3.5 - Calcite-Copper Penny
Luminescence:Non-fluorescent.
Luster:Vitreous (Glassy)
Streak:pale green
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