Uneven
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
MgB 3O 3(OH) 5 · 5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
MgAlBO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references