Guerinite

General Information: Chemical Formula:Ca5(AsO3OH)2(AsO4)2·9(H2O) Composition:(Molecular Weight = 920.22 gm)Calcium 21.78 % CaArsenic 32.57 % AsHydrogen 2.19 % H Oxygen 43.47 % O  Empirical Formula: Ca5(AsO3OH)2(AsO4)2·9(H2O)Physical Properties: Cleavage:[???] Perfect Color:colorless or white. Density:2.68 Diaphaniety:Transparent to Translucent Hardness:1.5 - Between Talc and Gypsum Luminescence:Fluorescent. Luster:Vitreous - Pearly Streak:whiteMore details...

Ca5H2(AsO4)4 9(H2O)