Witch-eye (man-made Mother of Pearl) ball 40mm, originating from China.

Gemstones are rare rocks that are usually cut and processed 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 involves looking at hardness, brittleness/splittability, and chemical resistance. Rarity. This looks at how often a product occurs in nature. Gemstones can be cut into many different shapes. The basic distinction is made between cabochon, where the gemstone is cut into a convex shape, and faceted, where 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 cleavage and polishing surfaces. Thus, they are processed into necklaces, earrings, bracelets, and many other types of jewelry, but gemstones are also used in the industry for processing. Famous gemstones include diamond, ruby, emerald, sapphire, aquamarine, topaz, tourmaline, amethyst, citrine, carnelian, opal, onyx, turquoise, lapis lazuli, and garnet. In the 18th and early 19th centuries, it was fashionable to make jewelry that incorporated someone's name or initials. When choosing the gemstones, people were guided by the first letter of the gemstone's name, and thus the gemstone alphabet was created. Similar acrostic jewelry was also made during the nineteenth century, in which sentiments were expressed through gemstones. Most well-known is the English 'regard' ring, an engagement ring where the word 'regard' (esteem) was formed by the gemstones ruby, emerald, garnet, amethyst, diamond.