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Biotite VIII - Phyllosilicates (Mica Group)

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Name		Biotite
Chemistry		K(Mg,Fe2+)3[(OH,F)2|(Al,Fe3+)Si3O10]
Hardness		2.5 - 3
Lustre		vitreous - pearly
Colour		dark brwon, black, dark green
Streak		white
Density [g/cm3]		2.8 - 3.2
Crystal habit		monoclinic, crystals pseudohexagonal, tabular
Cleavage, Fracture		[001] perfect
other characteristics and occurrences		fine to coarse grained, foliated, widely distributed, in many magmatic and metamorphic rocks

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© 2004 Büro für angewandte Mineralogie · Dr. Stephan Rudolph · D-47918 Tönisvorst

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