GIA's Gübelin Gem Project: Various Gems, Barite - Cuprite
Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.
A Prospectors’ Guide Map to the Gem Deposits of Sri Lanka
Sri Lanka is world famous for its gem wealth, but the actual extent of the deposits has never been determined.
Sri Lanka: The Gem Island
An overview of the many types of gem-quality material, and its inclusions, currently found in Sri Lanka.