Uneven, Uneven, Irregular, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Not Available
Na(Mg 3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)