Uneven, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Even
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Ca2Al3(SiO4)3(OH)
(Ca,Mn2+ )Si 3O 9Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references