Precious stones are a type of gemstone that is highly valued for its beauty, rarity, and durability. GEMS (4 letters) is a term used to refer to any precious stone, while JEWELS (6 letters) is a more specific term used to refer to GEMS that have been cut and polished for use in jewelry. OPALS (5 letters) are a type of precious stone that is known for its unique play of color, while EMERALDS (8 letters) are a type of green gemstone that is highly sought after for its beauty.