Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
[010] Perfect, [100] Distinct, [011] Distinct
Amethyst, Clear Quartz, Smoky Quartz, Cacoxenite, Rutile, Geothite, Lepidocrocite
{100} perfect; {110} and {1 1 0} good; {010} poor
(Ca,Mn2+ )Si 3O 9Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references