What are the Different Types of Precious Stones?
Precious stones, also known as gemstones, are minerals or rocks that that become collectible when they are cut or faceted and polished. In addition, precious stones are used in jewelry.
Precious stones can occur naturally, or they can be laboratory simulated. Natural precious stones come directly out of the ground or mine and are cut or faceted to the desired shape and size. These precious stones are usually the most popular among collectors and consumers, as well as the most expensive. Laboratory simulated precious stones are created in a lab. These manmade stones can still be considered precious stones, but are easier to come by and usually less expensive than their natural counterparts.
There are also organic precious stones. Amber, which is made from fossilized tree resin, is an example of an organic precious stone. Jet, which is a form of coal, is another organic precious stone. There are some precious stones that are too soft or fragile to be used in jewelry, such as single-crystal rhodochrosite. Although these precious stones cannot be used for jewelry, they are exhibited in museums and sought by collectors because of their beauty.
Gemologists use technical specifications to differentiate precious stones. The first consideration when identifying precious stones is the chemical composition. Diamonds, for example, are made of carbon, and rubies are made of aluminum oxide. Most precious stones are actually crystals, which are classified by a crystal system as cubic, trigonal, or monoclinic.
Precious stones are also classified into different groups, species, and varieties. The ruby, for example, is the red variety of the species corundum, which belongs to the spinel or hematite group. The emerald, aquamarine, bixbite, goshenite, heliodor, and morganite, on the other hand, are all varieties of the mineral species beryl.
Separating precious stones into these types of groups helps to identify their composition, their color, and their origin. Precious stones also have a refractive index, dispersion, specific gravity, hardness, cleavage, fracture, and lustre. Each of these features is important when assessing the value of the stone.
Written by Shannon Kietzman
