Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Uneven, UnevenArthur Thomas, Gemstones (2009)
Al 2SiO 5Arthur Thomas , Gemstones (2009)
Pb 26Ag 10Cu 24Cl 62(OH) 48 · 3H 2OWalter Schumann , Gemstones of the world (2001) More from other references