Kellyite

General Information: Chemical Formula:(Mn++,Mg,Al)3(Si,Al)2O5(OH)4 Composition:(Molecular Weight = 323.85 gm)Magnesium 7.51 % MgManganese 25.45 % MnAluminum 8.33 % AlSilicon 13.01 % SiHydrogen 1.24 % H Oxygen 44.46 % O  Empirical Formula: Mn2+1.5MgAl0.5Si1.5Al0.5O5(OH)4 Environment:Metamorphic Mn deposit with other Mn-silicates. IMA Status:Approved IMA 1974 Locality:Bald Knob, Sparta, Alleghany County, North Carolina, USA. Name Origin:Named for William Crowley Kelley (1929-), American geologist, University of Michigan.Physical Properties: Cleavage:[001] Perfect Color:golden yellow or lemon yellow. Density:3.07 Diaphaniety:Transparent Habits:Micaceous - Platy texture with "flexible" plates., Lath - Shaped like a small, thin plaster lath, tabular (rectangular) in shape., Tabular - Form dimensions are thin in one direction. Hardness:2.5 - Finger Nail Luster:Vitreous - Resinous Streak:yellowish whiteMore details...