Magnesioriebeckite

General Information: Chemical Formula:[ ]Na2(Mg3Fe++2)Si8O22(OH)2 Composition:(Molecular Weight = 841.27 gm)Sodium 5.47 % NaMagnesium 8.67 % MgIron 13.28 % FeSilicon 26.71 % SiHydrogen 0.24 % H Oxygen 45.64 % O  Empirical Formula: Na2Mg3Fe3+2(Si8O22)(OH)2 IMA Status:Approved IMA 1978Physical Properties: Cleavage:[110] Perfect Color:light blue, dark blue, black, or black blue. Density:3.19 Diaphaniety:Translucent to Subopaque Hardness:5 - Apatite Luster:Vitreous - Silky Streak:blue grayMore details...

Na2(Mg,Fe)3Fe2Si8O22(OH)2