Topaz furniture knob for doors or drawers, with a 25 mm gemstone ball.

Gemstones are rare minerals that are often cut and incorporated into jewelry and decorative objects. Gemstones possess the following characteristics: Beauty. This includes visual aspects such as color, luster, fire, transparency, and light effects. Durability. This considers hardness, fragility/cleavage, and chemical resistance. Rarity. This considers how often a product occurs in nature. Gemstones can be cut into many different shapes. The basic distinction is between cabochon, in which the gemstone is cut into a convex shape, and faceted, in which the surface of the gemstone is cut into various facets. When cutting, various properties of the stone are considered, including color, color distribution, inclusions, special light effects, dispersion, and fracture and cut surfaces. They are processed into necklaces, earrings, bracelets, and many other jewelry items, but gemstones are also used in industry for processing. Well-known gemstones include diamonds, rubies, emeralds, sapphires, aquamarines, topazes, tourmalines, amethysts, citrines, carnelians, opals, onyxes, turquoises, lapis lazuli, and garnets. In the 18th and early 19th centuries, it was fashionable to make jewelry incorporating a person's name or initials. The choice of gemstones was guided by the first letter of the gemstone's name, thus giving rise to the gemstone alphabet. Similar acrostic jewelry, expressing sentiments in gemstones, was also created during the 19th century. The most well-known is the English "regard" ring, an engagement ring in which the word "regard" was formed by the gemstones ruby, emerald, garnet, amethyst, and diamond.