Tenacity
-
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.313.95-4.10
1
7.18
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Fracture
-
Uneven
Cleavage
Indiscernible
{110} Perfect, {110} Perfect, {110} Perfect
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)
(Zn,Fe)SMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references