Uneven, Brittle, Metallic, Gemstones (2009)
Conchoidal, ConchoidalAnthony et al, Conchoidal, Brittle, Conchoidal
Na 2[Al 2Si 3O 10] · 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006) More from other references
(Zn,Cu)Al 6(PO 4) 4(OH) 8 · 4H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)