Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Na 8Al 6Si 6O 24(SO 4) · H 2OAnthony et al , Handbook of Mineralogy (2001)
ConchoidalWalter Schumann
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)