Uneven, UnevenArthur Thomas, Gemstones (2009)
Gems, Conchoidal, Brittle
Pb 26Ag 10Cu 24Cl 62(OH) 48 · 3H 2OWalter Schumann , Gemstones of the world (2001) More from other references
Ca 3Ti4+2(Fe3+2Si)O 12Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references