ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Perfect on {010}, good on {100}
{100} Perfect, {110} Good, {011} Distinct
Be 2BO 3(OH)Ulrich Henn and Claudio C.
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references