A
gemstone or
gem (also called a
fine gem,
jewel, or a
precious or
semi-precious 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) or
organic materials that are not minerals (such as
amber or
jet), 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 is another characteristic that lends value to a gemstone. 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
gemcutter; a
diamond worker is a
diamantaire.
