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
Poor on {110} and {100} very poor on {001}
Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4