1 Physical Properties
1.1 Tenacity
1.4 Solubility
1.6 Durability
Not Available
Not Available
1.7 Specific Gravity
2.4 Fracture
Uneven, Uneven, Gems, Sixth Edition (2006)
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
2.5 Cleavage
Perfect on [001], good on [010], imperfect on [110]
Indistinct
2.6 Mohs Hardness
2.9 Chemical Composition
Ca(70-90%)Na(30-10%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references