Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
ConchoidalWalter Schumann
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)
ConchoidalWalter Schumann
SiO 2Walter Schumann , Gemstones of the world (2001)