Ferrorichterite

General Information: Chemical Formula:Na(CaNa)Fe++5[Si8O22](OH)2 Composition:(Molecular Weight = 975.98 gm)Sodium 4.71 % NaCalcium 4.11 % CaIron 28.61 % FeSilicon 23.02 % SiHydrogen 0.21 % H Oxygen 39.34 % O  Empirical Formula: Na2CaFe2+5(Si8O22)(OH)2 IMA Status:Approved IMA 1978Physical Properties: Cleavage:[110] Perfect Color:brown, light green, dark green, or reddish brown. Density:3.46 Diaphaniety:Transparent to Translucent Hardness:5-6 - Between Apatite and Orthoclase Luster:Vitreous (Glassy)More details...

Na2Ca(Fe,Mg)5Si8O22(OH)2