Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
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.
Conchoidal, ConchoidalWalter Schumann
Distinct on {11 2 0}, imperfect on {10 1 1}
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references