Tenacity
Brittle
Brittle
Solubility
-
-
Durability
-
-
Specific Gravity
2.33-2.372.79-2.87
1
7.18
👆🏻
Fracture
Uneven
Conchoidal
Cleavage
Perfect on {001}, imperfect on {110}
{010} perfect; {100} good, interrupted; {101} indistinct; {001} in traces
Mohs Hardness
4.5-55.5-6
2
10
👆🏻
Chemical Composition
(K,Na)Ca4Si8O20(F,OH)•8(H2O)
NaBePO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references