Tenacity
Brittle
Brittle
Solubility
-
H₂SO₄
Durability
-
-
Specific Gravity
2.90-2.982.74-3.00
1
7.18
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Fracture
Conchoidal, ConchoidalWalter Schumann
Uneven
Cleavage
Distinct on {11 2 0}, imperfect on {10 1 1}
Distinct on {0001} imperfect on {11 2 0}
Mohs Hardness
7.5-85-5.5
2
10
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Chemical Composition
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Na 4(Ca,Ce) 2(Fe,Mn,Y)ZrSi 8O 22(OH,Cl) 2Ulrich Henn and Claudio C.