Vermiculite

General Information: Chemical Formula:(Mg,Fe++,Al)3(Al,Si)4O10(OH)2·4(H2O) Composition:(Molecular Weight = 504.19 gm)Magnesium 8.68 % MgAluminum 23.01 % AlIron 9.97 % FeSilicon 5.57 % SiHydrogen 2.00 % H Oxygen 50.77 % O  Empirical Formula: Mg1.8Fe2+0.9Al4.3SiO10(OH)2·4(H2O) Name Origin:From the Latin vermiculus, "little worm."Physical Properties: Cleavage:[001] Perfect Color:colorless, green, gray white, or yellow brown. Density:2.3 - 2.7, Average = 2.5 Diaphaniety:Translucent Habits:Lamellar - Thin laminae producing a lamellar structure., Scaly - Morphology like fish scales., Hardness:1.5-2 - Talc-Gypsum Luster:Vitreous - Dull Streak:greenish whiteMore details...

(Mg,Fe,Al)3(Al,Si)4O10(OH)2 4(H2O)