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