Tenacity
Brittle
-
Solubility
-
insoluble
Durability
-
-
Specific Gravity
1.792.36
1
7.18
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Fracture
Irregular/uneven
Uneven, Subconchoidal, Fibrous
Cleavage
Perfect on {10bar10}
[110] perfect, [101] good, [010] distinct
Mohs Hardness
2.53.5-4
2
10
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Chemical Composition
Ca6(Al,Si)2(SO4)2B(OH)4(OH,O)12•26(H2O)
Al 3(PO 4) 2(OH,F) 3 · 5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references