Uneven, Uneven, Irregular, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Uneven, Uneven, Gemstones of the world (2001) More from other references
Na(Mg 3)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012)
Ca 10Mg 2Al 4(SiO 4) 5(Si 2O 7) 2(OH) 4Ulrich Henn and Claudio C.