Tenacity
Brittle
-
Solubility
-
-
Durability
-
-
Specific Gravity
3.50-3.602.54-2.78
1
7.18
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Fracture
Uneven
Conchoidal
Cleavage
Good on {110}, (110) ^ (1 1 0) ≈87°; parting on {100}
Good in three directions
Mohs Hardness
65-6
2
10
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Chemical Composition
(Na,Fe,Ca)Si 2O 6Ulrich Henn and Claudio C.
K(Ca,Na) 2Si 4O 10(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references