A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal that, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli and opal) and occasionally organic materials that are not minerals (such as amber, jet, and pearl) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity and notoriety are other characteristics that lend value to gemstones.
Apart from jewelry, from the earliest antiquity engraved gems and hardstone carvings, such as cups, were major luxury art forms. A gem expert is a gemologist, a gem maker is called a lapidarist or gem cutter; a diamond cutter is called a diamantaire.(Copied through Wiki)
