Tenacity
-
Brittle
Solubility
-
Dilute acid
Durability
-
-
Specific Gravity
3.312.93-2.96
1
7.18
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Fracture
-
Subconchoidal, Conchoidal
Cleavage
Indiscernible
Distinct on {010}, imperfect {110} and {011}
Mohs Hardness
-99993.5-4
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)
CaCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references