Vesuvianite

General Information: Chemical Formula:Ca10Mg2Al4(SiO4)5(Si2O7)2(OH)4 Composition:(Molecular Weight = 1,422.09 gm)Calcium 28.18 % CaMagnesium 3.42 % MgAluminum 7.59 % AlSilicon 17.77 % SiHydrogen 0.28 % H Oxygen 42.75 % O  Empirical Formula: Ca10Mg2Al4(Si2O7)2(SiO4)5(OH)4 Environment:Contact metamorphic rocks and alpine veins. IMA Status:Approved IMA 1960 Locality:Mte. Somma, Vesuvius, Italy. Name Origin:Named after its locality.Physical Properties: Cleavage:[110] Indistinct, [100] Indistinct, [001] Indistinct Color:blue, brown, green, yellow, or white. Density:3.35 - 3.45, Average = 3.4 Diaphaniety:Subtransparent to subtranslucent Habits:Massive - Uniformly indistinguishable crystals forming large masses., Columnar - Forms columns, Granular - Generally occurs as anhedral to subhedral crystals in matrix. Hardness:6.5 - Pyrite Luminescence:Non-fluorescent. Luster:Vitreous - Resinous Streak:whiteMore details...