1 Physical Properties
1.1 Tenacity
1.2 Solubility
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Conchoidal, Conchoidal, Brittle
1.6 Cleavage
Poor to good on (001)
Perfect on {001}, good on {110}
1.7 Mohs Hardness
1.8 Chemical Composition
(Mg,Fe) 5(SiO 4) 2(F,OH) 2Ulrich Henn and Claudio C.
KNa 4Ca 4Si 8O 18(CO 3) 4(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)