Tenacity
-
Slightly sectile
Solubility
-
1.04 x 10−25 g per 100 ml water (Ksp at 25°C = 2 x 10−32)
Durability
-
-
Specific Gravity
3.262
1
7.18
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Fracture
Uneven
Uneven
Cleavage
None
Prismatic {10 1 0}, perfect
Mohs Hardness
-99992-2.5
2
10
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Chemical Composition
NaFe3+3Fe3+6(BO 3) 3Si 6O 18(O,OH) 4Anthony et al , Handbook of Mineralogy (2001)
HgSMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references