Ferrogedrite

General Information: Chemical Formula:[ ]Fe++5Al2Si6Al2O22(OH)2 Composition:(Molecular Weight = 941.68 gm)Aluminum 11.46 % AlIron 29.65 % FeSilicon 17.90 % SiHydrogen 0.21 % H Oxygen 40.78 % O  Empirical Formula: Fe2+5Al4Si6O22(OH)2 IMA Status:Approved IMA 1978 Name Origin:Named for its composition and the original gederite location at Heas, Gedres, France.Physical Properties: Cleavage:[110] Perfect, [010] Indistinct, [100] Indistinct Color:green, brownish green, brown, or greenish blue. Density:3.57 Diaphaniety:Transparent to Subopaque Hardness:5.5-6 - Knife Blade-Orthoclase Luster:Vitreous - Silky Streak:gray whiteMore details...