Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Distinct on {11 2 0}, imperfect on {10 1 1}
Perfect on {110} at 56° and 124°; partings on {010} and {100}
Be 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.