After cutting and polishing gem stones/precious stones are used in jewelry.
Gemstones/precious stones fall into different categories because of the composition.
E.g.: Diamonds-Made of carbon
Many gems are crystals and classified using a crystal system
E.g.: cubic, trogon, monoclinic
Classification of gem stones/precious stones
Gems/precious stones are classified classified into different groups, species and varieties.
E.g.: ruby is the red variety of species corundum
Other colours of corundum - sapphire
Value of the gems/precious stones
Value of a gem depends on the refractive index, dispersion, specific gravity, hardness, cleavage, fracture and luster. Value of a certain gem changes from the country to country. Coloured gem stones are prized specially for its great beauty and aesthetics.
Most of the gems are cut and polished before they fit into a particular purpose. Some gems are treated to increase their beauty and some of the non-gem stones are converted to gems by treating.
Methods of gem treating are,
Some gems are synthesized artificially
E.g.: Cubic zirconia