ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Metallic
ConchoidalGemdat.org, Management Team (2012), ConchoidalGemdat.org, Management Team (2012)
Be 2BO 3(OH)Ulrich Henn and Claudio C.
(Cu) 3(OH) 2(CO 3) 2 + Cu 2(CO 3)(OH) 2Gemdat.org , Management Team (2012)