Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Perfect on {001}, good on {110}
KNa 4Ca 4Si 8O 18(CO 3) 4(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
{100} Perfect, {110} Good, {011} Distinct
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references