Only three colored gemstones are considered precious. These are the sapphire, ruby and emerald, which have retained their prized positions among jewels due to their extraordinary colors and extreme rarity. Precious gemstones with good color and large size are very hard to come by. They are so rare that a natural, unenhanced, strongly colored stone can be worth as much per carat, or more, than a diamond of comparable quality. Despite the immense popularity of diamonds, colored precious gemstones have always been among the most popular and expressive forms of jewelry. The bright colors of colored gems give each a unique personality, and personal tastes in color often dictate preferences for particular stones.