ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001), Brittle, Metallic
ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
BeAlSiO 4(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Cu) 3(OH) 2(CO 3) 2 + Cu 2(CO 3)(OH) 2Gemdat.org , Management Team (2012)