GEM ENCYCLOPEDIA
FEATURED GEM
Diamond
Diamonds are among nature's most precious and beautiful creations.
THE FACTS
This hardest gem of all is made of just one element: carbon. It's valued for its colorless nature and purity. Most diamonds are primeval—over a billion years old—and form deep within the earth.
GIA’s Guide to Gemstones: Gem Encyclopedia
GIA’s Gem Encyclopedia is a virtual journey through the science and lore of gemstones from across the globe. Each precious stone page features additional detailed gemological information, a buyer’s guide, photos, videos & research.