1 Physical Properties
1.1 Tenacity
1.2 Solubility
1.3 Durability
Not Available
Not Available
1.4 Specific Gravity
1.5 Fracture
Conchoidal, Conchoidal, Brittle
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
1.6 Cleavage
Perfect on {001}, good on {110}
Indistinct
1.7 Mohs Hardness
1.8 Chemical Composition
KNa 4Ca 4Si 8O 18(CO 3) 4(OH,F) · H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references