Difference between revisions of "Template:Tourmaline"

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| Habit || Trigonal prisms with convex faces
 
| Habit || Trigonal prisms with convex faces
 
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| Fracture || Concoidal
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| Fracture || Conchoidal
 
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|-
 
| Hardness || 7.5
 
| Hardness || 7.5

Latest revision as of 06:11, 8 October 2007

Tourmaline
Chemical composition Complex borosilicate
Crystal system Trigonal
Habit Trigonal prisms with convex faces
Fracture Conchoidal
Hardness 7.5
Optic nature Uniaxial -
Refractive index 1.62 - 1.64
Birefringence 0.014-0.021 (up to 0.039)
Dispersion Low, 0.018
Specific gravity 3.06 (3.01-3.11)
Lustre Vitreous
Pleochroism Weak to strong