Splintery, Granular, Splintery, Granular, Gemstones (2009)
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
Mg 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references