Zykaite

General Information: Chemical Formula:Fe+++4(AsO4)3(SO4)(OH)·15(H2O) Composition:(Molecular Weight = 1,023.45 gm)Iron 21.83 % FeArsenic 21.96 % AsHydrogen 3.05 % H Sulfur 3.13 % S Oxygen 50.03 % O  Empirical Formula: Fe3+4(AsO4)3(SO4)(OH)·15(H2O) IMA Status:Approved IMA 1978 Locality:Kank, near Kutna Hora, Czech Republic. Name Origin:Named for Vaclav Zyka (1926-), Czech geochemist.Physical Properties: Color:greenish white or gray white. Density:2.5 Diaphaniety:Translucent Habits:Nodular - Tuberose forms having irregular protuberances over the surface., , Hardness:2 - Gypsum Luster:Earthy (Dull) Streak:whiteMore details...