Tags: Chemical Substance, Mineral.
Aenigmatite also known as Cossyrite after Cossyra the ancient name of Pantelleria is a sodium iron titanium inosilicate mineral. The chemical formula is Na2Fe2+5TiSi6O20 and its structure consists of single tetrahedral chains with a repeat unit of four and complex side branches. It forms brown to black triclinic lamellar crystals. It has Mohs hardness of 5.5 to 6 and specific gravity of 3.74 to 3.85. Aenigmatite forms a solid-solution series with wilkinsonite Na2Fe2+4Fe3+2Si6O20.
