Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{111} Indistinct, {111} Indistinct, {111} Indistinct
(K,Cs)Al 4Be 4(B,Be) 12O 28Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Uneven, Conchoidal to uneven, ConchoidalWalter Schumann
Distinct on {110}, imperfect on {010}, poor on {001}