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
Distinct on {0001} imperfect on {11 2 0}
Na 4(Ca,Ce) 2(Fe,Mn,Y)ZrSi 8O 22(OH,Cl) 2Ulrich Henn and Claudio C.