Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
{001} Perfect, {010} Good
KAlSi 3O 8Arthur Thomas , Gemstones (2009)
Conchoidal, ConchoidalWalter Schumann
Perfect in three directions
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references