Tenacity
-
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
3.2-3.42.79-2.87
1
7.18
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Fracture
Uneven
Conchoidal
Cleavage
Perfect on [001] imperfect on [100]
{010} perfect; {100} good, interrupted; {101} indistinct; {001} in traces
Mohs Hardness
35.5-6
2
10
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Chemical Composition
(K,Na) 3(Fe2+ ,Mn) 7Ti 2Si 8O 24(O,OH) 7Anthony et al , Handbook of mineralogy (2001)
NaBePO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references