Emeralds, another popular gemstone, derive their lush green color from trace amounts of chromium or sometimes vanadium. Emeralds are a variety of the mineral beryl, which is primarily composed of ...

Gemstones are valued based on the Four Cs - color, clarity, cut, and carat. Precious stones include diamonds, sapphires, ...

GIA’s laboratories use advanced instrumentation and research to deliver accurate grading, identification, and origin ...

Compared to common opal, which is usually one color, black opal exhibits many different colors contrasted by a dark body tone. Frederick: It's simply the most stunning gemstone on the planet.