Gemstones, or Semi-Precious stones, are minerals and sometimes rocks or organic matter (other than the precious stones: diamonds, rubies, emeralds, and sapphires) that, when cut correctly, are regarded as very beautiful and are often used in jewelry making. Gemstones are categorized into different species, groups, and varieties. Different gemstones have different meanings, symbolic values, and uses. The monetary value and rarity of a gemstones also varies greatly from stone to stone. The value of a gemstone is determined by it’s color, cut, clarity, rarity, origin, and optical characteristics. Because special characteristics define each type of gemstone, each gemstone are evaluated against the characteristics of its type.