A gemstone (also called a fine gem, jewel, precious stone, or
semiprecious stone) is a piece of mineral crystal which, 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 earliest antiquity engraved gems and
hardstone carvings, such as cups, were major luxury art forms. A
gem maker is called a lapidary or gem cutter; a diamond cutter is
called a diamantaire.
