Gemstones are valued based on the Four Cs - color, clarity, cut, and carat. Precious stones include diamonds, sapphires, rubies, and emeralds. Semi-precious stones are evaluated on their rarity ...

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

However, in 1912, the National Association of Jewelers released a list of “modern birthstones” that included only transparent gems (the list that appears above). This was apparently done to ...