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Common Treatment of Our Colored Gemstones

Common Treatment of Our 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.

While white diamonds are typically untreated, 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.
Type Treatment Methods Care Advice
Abalone shell Dyeing, coating for protection, stabilizing to reduce porosity Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaner or steamer. Avoid sudden temperature changes, rough wear, heat, chemicals, and acids. Avoid perfumes and hairsprays and be mindful of scratching.
Agate Dyeing, bleaching, heating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually okay to use. Avoid high heat.
Alexandrite No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually okay to use.
Amazonite Impregnating with a colorless wax, paraffin or oil to improve appearance Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners, steamers, and chemicals.
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 Warm soapy water and a soft cloth are safe. Hard bristle brushes may leave scratches. Avoid ultrasonic cleaners and steamers.
Amethyst Almost all are heated to improve appearance or deepen color Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually okay to use. Avoid steamers. Do not expose to intense heat.
Ametrine Heating Warm soapy water and a soft cloth are safe, ultrasonic is usually safe. Avoid the steamer. Do not expose to intense heat.
Ammolite Lacquer coating Warm soapy water and a soft cloth are safe. A hard bristle brush may leave scratches on lacquered material. Avoid ultrasonic cleaners, steamers, and solvents.
Andalusite Heating (rarely) to produce pink color from some green Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers.
Apatite Heating, irradiating Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners and steamers.
Aquamarine Heating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are safe if no liquid inclusions or feathers are present.
Aventurine Heating, dyeing, and bleaching Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners, steamers, abrasives, solvents, and heat.
Beryl Heating, irradiating (see varieties for varietal specific information) Warm soapy water and a soft cloth are safe. Avoid strong detergents and high heat (see varieties for varietal specific information).
Bloodstone Dyeing, heating Warm soapy water is safe. Ultrasonic cleaners and steamers are usually safe. Avoid high heat.
Carnelian Dyeing, heating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually safe. Avoid high heat.
Chalcedony Dyeing, heating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually safe. Avoid high heat.
Chrysoprase Dyeing, heating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually safe. Avoid high heat.
Citrine Heating, irradiating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers. Do not expose to intense heat.
Coral Bleaching, dyeing Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners and steamers. Avoid high heat and chemicals.
Corundum Dyeing, heating Warm soapy water and a soft cloth are safe. Avoid chemicals, heat, and ultrasonic cleaners.
Cubic zirconia Lab created. No commercial treatments known Warm soapy water, soft cloth, ultrasonic cleaners, and steamers are all safe.
Diamond Diamonds in the D-Z color range are typically untreated. Fancy colored diamonds are usually irradiated and heated to enhance color. Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually safe unless the diamond contains feathers.
Diopside No commercial treatments known Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners and steamers. Avoid intense heat and rough handling.
Druzy Dyeing to enhance appearance, sometimes coating to create iridescence Warm soapy water and a soft cloth are safe. Avoid strong detergents and extreme heat.
Emerald Impregnating with oil, wax, or resin to improve appearance. Dying with color agents. Soft, damp cloth is safe. Avoid ultrasonic cleaner, steamers, strong detergents, household chemicals, cosmetics, hair spray, and perfume. Refrain from sudden temperature changes.
Eudialyte No commercial treatments known Cool soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Be mindful of scratching.
Feldspar Wax infusing Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners and steamers.
Fluorite Heating, irradiating Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners , steamers, and heat.
Garnet No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers and sudden temperature changes.
Hematite No commercial treatments known Warm soapy water, a soft cloth, ultrasonic cleaners, and steamers are all safe.
Howlite Dyeing Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners, steamers, rough handling, solvents, and extreme heat.
Iolite No commercial treatments known Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid abrupt changes in heat.
Jade Dyeing or heating to enhance color. Impregnating with paraffin wax to hide surface cracks. Warm soapy water, a soft cloth, ultrasonic cleaners, and steamers are all safe. Avoid high heat and chemicals.
Jasper Dyeing, heating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually okay to use. Avoid high heat.
Kunzite Irradiation, heating Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners, steamers, rough handling, and abrupt temperature changes. Prolonged exposure to light, particularly UV and sunlight, will cause fading.
Kyanite No commercial treatments known Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling.
Labradorite No commercial treatments known Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling and heat.
Lapis Lazuli Impregnating with colorless wax and/or dyeing to enhance color Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid heat and solvents.
Larimar Stabilizing to increase durability and improve appearance Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling, heat, and chemicals.
Malachite Dyeing, coating with colorless wax, or impregnating with paraffin or epoxy resin to improve polish and hide small cracks Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling, heat, and chemicals.
Marcasite No commercial treatments known Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid acids or chemicals.
Moissanite Lab created Warm soapy water and soft cloth are safe. Ultrasonic cleaners and steamers are usually safe.
Moonstone No commercial treatments known Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling and heat.
Morganite Heating, irradiating Warm soapy water and a soft cloth are safe. Avoid strong detergents and high heat.
Mother of Pearl Dyeing, coating for protection, stabilizing to reduce porosity Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid sudden temperature changes, rough wear, heat, chemicals, acids, perfumes, and hairsprays.
Nephrite Dyeing, heating and infusion with paraffin wax Warm soapy water, a soft cloth, ultrasonic cleaners, and steamers are all safe. Avoid solvents and heat.
Obsidian No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers, heat, and chemicals.
Onyx Dyeing, heating, irradiating Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually okay to use. Avoid high heat.
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. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid contact with cosmetics, hair spray, perfume and household chemicals. Refrain from solvents, repolishing, sharp blows, and changes in temperature.
Pearls Bleaching, dyeing, irradiating, coating Wipe with very soft cloth after wearing. Mild soap with water is safe for a more thorough cleaning (if strung, be sure string is completely dry before wearing). Avoid ultrasonic cleaners, steamers, heat, all chemicals, perfumes, and perspiration. Store away from other items and avoid rough wear.
Pearls—Shell Man-made Mild soap with water and a soft cloth are safe (if strung, be sure string is completely dry before wearing). Not susceptible to damage from sweat, perfumes, etc. like their natural counterpart.
Peridot No commercial treatments known Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners, steamers, acids, and sudden temperature changes.
Prasiolite Irradiating/annealing to alter color Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers. Do not expose to intense heat.
Prehnite No commercial treatments known Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners, steamers, and sudden temperature changes.
Pyrite No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners and steamers are usually safe. Avoid heat and nitric acid.
Quartz Dyeing, heating, irradiating, quench crackling, and sometimes coating. Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Do not expose to intense heat. Avoid steamers, rough handling, strong solvents, and prolonged exposure to strong light.
Rutilated quartz No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers.
Rhodochrosite No commercial treatments known Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Be mindful of scratching or chipping.
Rhodolite No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers and sudden temperature changes.
Rhodonite Dyeing Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling and heat.
Ruby Heating, diffusing, dyeing, oiling Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid harsh chemicals, strong detergents, solvents, and recutting or repolishing.
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. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid strong detergents, common household chemicals, heat, pressure, recutting or repolishing, and jeweler's torches.
Sapphire Heating, diffusing, dyeing Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid harsh chemicals, strong detergents, solvents, and recutting or repolishing.
Diffused Sapphire Color inducing by lattice diffusion of titanium from an external source. Always heated to improve appearance. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid strong detergents, common household chemicals, heat, pressure, recutting or repolishing, and jeweler's torches.
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. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid strong detergents, common household chemicals, heat, pressure, recutting or repolishing, and jeweler's torches.
Sodalite Dyeing Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid cleaners, chemicals, and rough handling.
Spinel Heating Warm soapy water, ultrasonic cleaners, and steamers are all usually safe. Light colored stones may fade under intense heat.
Tanzanite Heating Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid rough handling.
Tigers eye Heat treating, dyeing, bleaching Warm soapy water and soft cloth are safe. Ultrasonic cleaners are usually safe. Avoid steamers and abrupt temperature changes.
Topaz Heating, irradiation, coating Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid high heat and rough handling.
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. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid sudden changes in heat. Parti-colored stones tend to be more fragile at the color boundaries.
Tsavorite No commercial treatments known Warm soapy water and a soft cloth are safe. Ultrasonic cleaners are usually safe (unless liquid inclusions are present). Avoid steamers and abrupt temperature changes.
Turquoise Dyeing, wax or plastic impregnating, sometimes with a colorant added. The proprietary Zachary process to improve durability and appearance. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid high heat and chemicals.
Reconstituted Turquoise This is a larger stone created from smaller turquoise pieces. Other treatments include stabilizing, coloring, and adding metallic veining. Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid high heat, sudden temperature changes, and chemicals.
Stabilized Turquoise Stabilizing to increase durability and improve appearance Warm soapy water and a soft cloth are safe. Never use ultrasonic cleaners or steamers. Avoid hot water and household chemicals.
Zircon Heating (colorless and blue stones are almost always heated) Warm soapy water and a soft cloth are safe. Avoid ultrasonic cleaners and steamers. Avoid rough wear as these stones can abrade.

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