HOME NEW Pearl Education Beading Q & A Tools Jewelry Tech Video Jewelry Glossary

Common Treatments of Colored Gemstones


Almost all colored gemstones sold by jewelers today are enhanced. Many of the processes have been used for hundreds of years and are accepted by the American Gem Trade Association. Colored gemstones without treatment are rare and incredibly expensive.

When it comes to treated gemstones, Ross-Simons only accepts the treatments that we feel give our customers a high-quality gemstone at the very best value. Our gemologists thoroughly inspect our gemstones to ensure our high standards.

White diamonds are never treated or enhanced. However, all of our colored diamonds have been treated unless described as "natural."

Here are descriptions for the common treatments of our colored gemstones:

Bleaching: This process lightens a gemstone through heat or chemicals.

Coating: This process coats the gemstone's exterior with oil, wax or resin enhance the gemstone's surface, protect it, give it a special effect, or make it more durable.

Dyeing: This process adds a coloring agent into a gemstone to change its color, improve uniformity, or enhance its current color.

Filling: This process improves a gemstone's appearance and clarity by adding glass or another agent.

Heating: This process uses intense heat to change or enhance a gemstone's color or clarity.

Impregnation: This process introduces resin, oil, plastic, polymer, colorless wax or other hardening agents into the gemstone to increase its durability or enhance its appearance.

Irradiation: This process uses radiation to change a gemstone's color. A heating process commonly follows the irradiation.

Oiling: This process improves a gemstone's appearance with the application of a colorless wax, oil or paraffin.

Reconstituted: Reconstitution is a process that involves molding ground-up natural gemstone into a solid stone with the use of a binding agent.

Stabilized: "Stabilized" means that the gemstone has been treated with a clear epoxy, resin, or hardening agent in order to protect its color and prevent it from fracturing.