Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Uneven
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Mn 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006)
Al 2Be 3Si 6O 18Martin H.