GIA Gem Encyclopedia | Complete List Of Gemstones
Each precious stone page features additional detailed gemological information, a buyer’s guide, photos, videos & research. Show Filters Filter By Color
What is Topaz Gemstone | Topaz Stone – GIA
Topaz is a precious stone, typically colorless, yellow & is Allochromatic, which means that its color is caused by defects in its crystal structure.
Emerald Gemstone | Emerald Stone - GIA
Color. The most desirable emerald colors are bluish green to pure green, with vivid color saturation.
Sapphire Gemstone | Sapphire Stone - GIA
Color. Sapphires come in a variety of colors. Preferred sapphires have strong to vivid color saturation, regardless of hue.
Garnet Gemstone | Garnet Stone - GIA
Red garnets have a long history, but modern gem buyers can pick from a rich palette of garnet colors: greens, oranges, pinkish oranges, deeply saturated purplish reds, and even some …
What Is Jade Gemstone | Jade Stone – GIA
Color. The finest jadeite—almost transparent with a vibrant emerald-green color—is known as “imperial jade.”
Opal Gemstone | Opal Stone - GIA
Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “Outback.” It is known for its unique display of flashing rainbow colors.
Ruby Gemstone | Ruby Stone - GIA
Color. Color is the most significant factor affecting a ruby’s value: Fine gems are a pure, vibrant red to slightly purplish red.
Amethyst Gemstone | Amethyst Stone - GIA
Amethyst Gemstone is the purple variety of the Quartz mineral. Amethyst’s purple color can range from a light lilac to a deep, intense royal purple, and from brownish to vivid.
What Is Morganite Gemstone | Morganite Stone – GIA
Morganite’s subtle color is caused by traces of manganese. Because morganite has distinct pleochroism—pale pink and a deeper bluish pink—it’s necessary to orient the rough carefully …