Physical Properties
Tenacity
Not Available
Brittle
Solubility
Not Available
Not Available
Durability
Not Available
Not Available
Specific Gravity
2.90-3.14
2.60-2.65
Fracture
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Uneven, Gems, Sixth Edition (2006), Uneven, Conchoidal
Cleavage
Imperfect; basal
Perfect on {001}, very good on {010}, imperfect on {110}
Mohs Hardness
7.5-8
6-6.5
Chemical Composition
(Be,Cs) 3Al 2Si 6O 18 · 0.5H 2OUlrich Henn and Claudio C.
NaAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
