Aluminocopiapite

General Information: Chemical Formula:Al2/3Fe+++4(SO4)6O(OH)2·20(H2O) Composition:(Molecular Weight = 1,212.08 gm)Aluminum 1.48 % AlIron 18.43 % FeHydrogen 3.49 % H Sulfur 15.87 % S Oxygen 60.72 % O  Empirical Formula: Al0.6666Fe3+4(SO4)6(OH)2·20(H2O)Physical Properties: Color:yellow. Diaphaniety:Transparent to Translucent Hardness:2.5-3 - Finger Nail-Calcite Luster:Earthy (Dull) Streak:light yellowMore details...

Al0.66Fe4(SO4)6(OH)2 20(H2O)