Ferroholmquistite

General Information: Chemical Formula:[ ](Li2Fe++3Al2)Si8O22(OH)2 Composition:(Molecular Weight = 846.07 gm)Lithium 1.64 % LiAluminum 6.38 % AlIron 19.80 % FeSilicon 26.56 % SiHydrogen 0.24 % H Oxygen 45.38 % O  Empirical Formula: Li2Fe2+3Al2(Si8O22)(OH)2 IMA Status:Approved IMA 1978 Name Origin:The name reflects its composition and relationship to holmquistite..Physical Properties: Color:black. Hardness:5-6 - Between Apatite and OrthoclaseMore details...

Li2(Fe,Mg)Al2Si8O22(OH)2