Tenacity
Brittle
-
Solubility
-
insoluble
Durability
-
-
Specific Gravity
3.20-3.322.36
1
7.18
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Fracture
Uneven, Conchoidal
Uneven, Subconchoidal, Fibrous
Cleavage
Poor
[110] perfect, [101] good, [010] distinct
Mohs Hardness
6-6.53.5-4
2
10
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Chemical Composition
(Mg,Fe2+ ) 7(SiO 4) 3(F,OH) 2Anthony et al , Handbook of mineralogy (2001)
Al 3(PO 4) 2(OH,F) 3 · 5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references