Gemstone Treatments and Enhancements
Below is a list of possible treatments and/or enhancements
Abalone shell | Dyeing, coating for protection, stabilizing to reduce porosity |
Agate | Dyeing, bleaching, heating |
Alexandrite | No commercial treatments known |
Amazonite | Impregnating with a colorless wax, paraffin or oil to improve appearance |
Amber | Heating in oil to clarify cloudy amber, heating (sometimes with oil) to produce disk-like fractures creating sun-spangled amber, heating to darken light amber, and dyeing |
Amethyst | Almost all are heated to improve appearance or deepen color |
Ametrine | Heating |
Ammolite | Lacquer coating |
Andalusite | Heating (rarely) to produce pink color from some green |
Apatite | Heating, irradiating |
Aquamarine | Heating |
Aventurine | Heating, dyeing, and bleaching |
Beryl | Heating, irradiating (see varieties for varietal specific information) |
Bloodstone | Dyeing, heating |
Carnelian | Dyeing, heating |
Chalcedony | Dyeing, heating |
Chrysoprase | Dyeing, heating |
Citrine | Heating, irradiating |
Coral | Bleaching, dyeing |
Corundum | Dyeing, heating |
Cubic zirconia | Lab created. No commercial treatments known |
Diamond | Diamonds in the D-Z color range are typically untreated. Fancy colored diamonds are usually irradiated and heated to enhance color. |
Diopside | No commercial treatments known |
Druzy | Dyeing to enhance appearance, sometimes coating to create iridescence |
Emerald | Impregnating with oil, wax, or resin to improve appearance. Dying with color agents. |
Eudialyte | No commercial treatments known |
Feldspar | Wax infusing |
Fluorite | Heating, irradiating |
Garnet | No commercial treatments known |
Hematite | No commercial treatments known |
Howlite | Dyeing |
Iolite | No commercial treatments known |
Jade | Dyeing or heating to enhance color. Impregnating with paraffin wax to hide surface cracks. |
Jasper | Dyeing, heating |
Kunzite | Irradiation, heating |
Kyanite | No commercial treatments known |
Labradorite | No commercial treatments known |
Lapis Lazuli | Impregnating with colorless wax and/or dyeing to enhance color |
Larimar | Stabilizing to increase durability and improve appearance |
Malachite | Dyeing, coating with colorless wax, or impregnating with paraffin or epoxy resin to improve polish and hide small cracks |
Marcasite | No commercial treatments known |
Moissanite | Lab created |
Moonstone | No commercial treatments known |
Morganite | Heating, irradiating |
Mother of Pearl | Dyeing, coating for protection, stabilizing to reduce porosity |
Nephrite | Dyeing, heating and infusion with paraffin wax |
Obsidian | No commercial treatments known |
Onyx | Dyeing, heating, irradiating |
Opal | Impregnating with wax, oil, or plastic to improve play of color and/or to prevent or disguise cracking. Treatment with aniline dye, silver nitrate, or sugar carbonized by acid to create appearance of black opal. Smoke impregnating to create appearance of black opal. |
Pearls | Bleaching, dyeing, irradiating, coating |
Pearls – Shell | Man-made |
Peridot | No commercial treatments known |
Prasiolite | Irradiating/annealing to alter color |
Prehnite | No commercial treatments known |
Pyrite | No commercial treatments known |
Quartz | Dyeing, heating, irradiating, quench crackling, and sometimes coating. |
Rock crystal quartz | No commercial treatments known |
Rutilated quartz | No commercial treatments known |
Rhodochrosite | No commercial treatments known |
Rhodolite | No commercial treatments known |
Rhodonite | Dyeing |
Ruby | Heating, diffusing, dyeing, oiling |
Glass filled ruby | Filling of surface-breaking cavities or fissures with colorless glass or fluxes during the heat treatment process. Intended to improve clarity and color and may add weight. |
Sapphire | Heating, diffusing, dyeing |
Diffused sapphire | Color inducing by lattice diffusion of titanium from an external source. Always heated to improve appearance. |
Glass filled sapphire | Filling of surface-breaking cavities or fissures with colorless glass or fluxes during the heat treatment process. Intended to improve clarity and color and may add weight. |
Sodalite | Dyeing |
Spinel | Heating |
Tanzanite | Heating |
Tigers eye | Heat treating, dyeing, bleaching |
Topaz | Heating and irradiating |
Tourmaline | Heating to improve color, irradiating to create color, impregnating with oil and/or resin to improve appearance. Acid treating and impregnating with plastic or epoxy filler for tourmalines displaying chatoyancy. |
Tsavorite | No commercial treatments known |
Turquoise | Dyeing, wax or plastic impregnating, sometimes with a colorant added. The proprietary Zachary process to improve durability and appearance. |
Reconstituted turquoise | This is a larger stone created from smaller turquoise pieces. Other treatments include stabilizing, coloring, and adding metallic veining. |
Stabilized turquoise | Stabilizing to increase durability and improve appearance |
Zircon | Heating (colorless and blue stones are almost always heated) |