gem·stones | ˈjem-ˌstōn
A general term which includes diamonds, sapphires, emeralds, chalcedony, agates, heliotropes, onyx, tourmaline, chrysolite, rubies, spinel, topaz, turquoise, zircon, and more.
Gemstones, also listed as jewels, precious stones, or gems, are mineral crystals that are mined from the ground or produced in a lab, and when cut and polished, are used in jewelry of some form. There are some types of gemstones that are not considered minerals but that may also be used as jewelry, including lapis lazuli and opal. Gems are classified by a number of factors including hardness, color, shape, and brightness. Depending on the type of gemstone, different characteristics may be used to indicate quality. The most common gemstones in jewelry include diamonds, emeralds, sapphires, agates, rubites, topaz, garnets, and many others.