Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Uneven
Splintery, Granular, Splintery, Granular, Gemstones (2009)
Mn 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006)
Ca 2(Mg,Fe) 5(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references