Leifite

General Information: Chemical Formula:Na2(Si,Al,Be)7(O,OH,F)14 Composition:(Molecular Weight = 425.47 gm)Sodium 10.81 % NaBeryllium 1.48 % BeAluminum 13.32 % AlSilicon 23.76 % SiHydrogen 0.76 % H Oxygen 43.62 % O Fluorine 6.25 % F  Empirical Formula: Na2Si3.6Al2.1Be0.7O8.4(OH)3.2F1.4 Environment:Cavities in alkali-pegmatite veins. Locality:Narsarsuk, Greenland.Physical Properties: Cleavage:[???] Good, [???] Good Color:colorless or white. Density:2.57 Diaphaniety:Transparent Habits:Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline)., Pseudo Hexagonal - Crystals show a hexagonal outline., Hardness:6 - Orthoclase Luster:Vitreous (Glassy) Streak:whiteMore details...