Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
SiO 2Ulrich Henn and Claudio C.
{100} Perfect, {110} Good, {011} Distinct
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references