Home Tourmaline
VIII - Cyclosilicates
Crystal habit of Tourmaline Tourmaline Tourmaline

Name   Tourmaline
Chemistry   Na(Mg,Fe3Al6[(OH)4|(BO3)3|Si6O18]
Hardness   7
Lustre   vitreous
Colour   colourless and in all colours
Streak   white 
Density [g/cm3]   3.0 - 3.3
Crystal habit   trigonal, crystals columnar with ditrigonal cross section, striated
Cleavage, Fracture   fracture conchoidal to uneven
other characteristics and occurrences   schorl     = black variety
achroite   = colourless
indicolite = blue
rubellite  = red, pink
verdelite  = green
in pegmatites, inclusions in quartz (tourmalinated quartz)

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