Gems, Sixth Edition (2006), Gems, Sixth Edition (2006), Uneven
Uneven, Uneven, Irregular, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Na(90-70%)Ca(10-30%)(Al,Si)AlSi 2O 8Michael OâDonoghue , Gems, Sixth Edition (2006)
Na(Mg 3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)