Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
5.50-5.902.54-2.78
1
7.18
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Fracture
Conchoidal
Conchoidal
Cleavage
On {10 1 0}, perfect; parting on {000 1 }
Good in three directions
Mohs Hardness
45-6
2
10
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Chemical Composition
(Zn,Mn2+ )OMichael OâDonoghue , Gems, Sixth Edition (2006)
K(Ca,Na) 2Si 4O 10(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references