Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.25-3.455.00-5.30
1
7.18
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Fracture
Conchoidal, Uneven
Uneven, ConchoidalWalter Schumann, Conchoidal
Cleavage
Good on {110}
None, may show partings on {0001} and {10 1 1}
Mohs Hardness
6.56
2
10
👆🏻
Chemical Composition
Mg 3Al 6(Si,Al,B) 5O 21(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Fe 2O 3Arthur Thomas , Gemstones (2009)