Redingtonite

General Information: Chemical Formula:(Fe++,Mg,Ni)(Cr,Al)2(SO4)4·22(H2O) Composition:(Molecular Weight = 918.74 gm)Magnesium 0.79 % MgAluminum 1.47 % AlChromium 8.49 % CrIron 3.65 % FeNickel 0.64 % NiHydrogen 4.83 % H Sulfur 13.96 % S Oxygen 66.17 % O  Empirical Formula: Fe2+0.6Mg0.3Ni0.1Cr1.5Al0.5(SO4)4·22(H2O) Locality:Redington mine, Knoxville, Napa Co., California. Name Origin:Named after it's locality.Physical Properties: Color:white, light violet, or light purple. Density:1.761 Diaphaniety:Transparent Habits:Fibrous - Crystals made up of fibers., , Hardness:2 - Gypsum Luminescence:Non-fluorescent. Luster:Silky Streak:whiteMore details...