Tenacity
-
Brittle
Solubility
-
insoluble
Durability
-
-
Specific Gravity
3.316.86-7.03
1
7.18
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Fracture
-
Subconchoidal, Uneven, Conchoidal, Irregular
Cleavage
Indiscernible
{100} imperfect, {110} indistinct; partings on {111} or {011}
Mohs Hardness
-99996-7
2
10
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Chemical Composition
NaFe 3+ 3 Al 6 (BO 3 ) 3 Si 6 O 18 (O,F,OH) 4 Anthony et al, Handbook of mineralogy (2001)
SnO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references