Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
K(Ca,Na) 2Si 4O 10(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Perfect on {001}, very good on {010}, imperfect on {110}
NaAlSi 3O 8Michael OâDonoghue , Gems, Sixth Edition (2006)