Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Uneven
(Mg,Fe2+ )Al 2O 4Gemdat.org , Management Team (2012) More from other references
Mn 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006)