ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Uneven
CaBe 2(PO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006)
Mg 3Al 6(Si,Al,B) 5O 21(OH)Walter Schumann , Gemstones of the world (2001) More from other references