Splintery, Granular, Splintery, Granular, Gemstones (2009)
ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
Be 2BO 3(OH)Ulrich Henn and Claudio C.