Brittle, Metallic, Brittle, Metallic
Uneven, Conchoidal, Brittle, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
{001} Perfect, {110} Distinct, {101} Distinct
Poor/indistinct on {1120} and {1011}
Be 4Si 2O 7(OH) 2Anthony et al , Handbook of mineralogy (2001)
Na(Li 1.5Al 1.5)Al 6(Si 6O 18)(BO 3) 3(OH) 3(OH)Gemdat.org , Management Team (2012) More from other references