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) |