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 and ...

The highest-quality gems have no inclusions visible to the naked eye, are vibrant in color, and are typically more expensive gems like rubies, sapphires and emeralds. GIA would rate the highest ...