Colored Gemstone Enhancement Processes
There are many methods of enhancing colored gemstones. We describe the most common enhancements below. For more information on colored gemstone enhancements, see the American Gem Trade Association’s Gemstone Information Manual.
- Heat Treatment
The application of heat to enhance the color and/or clarity of gemstones has been a common practice around the globe for centuries. It is part of the standard polishing and finishing process for many colored gemstones. As such, it is accepted by the jewelry industry and the American Gem Trade Association. The enhanced color and/or clarity of heat-treated gemstones is permanent.
The filling of a gem material with an oil, wax, glass, resin or other material, colored or colorless, to improve appearance. This process began centuries ago by gemstone merchants who found that immersing emeralds in oil or waxes made them look clearer to the unaided eye. This practice continues today with many colored gemstones.
The use of wax, resin or oil applied to the exterior of a porous colored gemstone to protect the natural substance, and to improve sturdiness and appearance.
The application of chemicals or other elements to lighten or enhance color consistency.
The act of adding coloring agents so that they permeate a colored gemstone to enhance or alter color.
The alteration of a gemstone’s color through the use of radiation. This is often followed by a heating process. The enhanced color of irradiated gemstones is permanent.
- New and Future Technologies
Techniques for enhancing colored gemstones, either detectable or otherwise, are continually being developed. These may be difficult, or in rare cases, impossible to detect, even for the most sophisticated laboratory. Blue Nile will continue to work with industry groups and gemological experts who are committed to the identification and disclosure of new and future techniques in order to maintain our stringent quality standards.
Basic Gemstone Care
While gemstones are durable, they require varying levels of care. For example, some gemstones are especially vulnerable to household chemicals and temperature changes. Cleaning gemstones presents special challenges. While many gemstones should be cared for by following our basic care guidelines below, please refer to our Gemstone and Pearl Care and Enhancement Overview to understand the care requirements for your specific stone. If you still have questions, please contact Blue Nile customer service.
After removing your gemstone jewelry, clean it by following the directions on a non-abrasive jewelry cleaner. Make sure that the jewelry cleaner specifies that it is safe to use with your gemstone. Use a soft cloth to remove any remaining dirt or other residue.
Store your gemstone jewelry in a lined case or a soft cloth, so the gems do not touch each other or parts of other jewelry. Gemstones are harder than gold, silver, or platinum and can scratch the surfaces of your other fine jewelry if they are not kept separate.
While it’s true that gemstones such as ruby and sapphire are second only to diamond on the hardness scale, it is not a measurement of their indestructibility. It means that these gemstones are able to resist scratching almost as well as a diamond. Abrasive surfaces, harsh chemicals, and sharp blows can damage even the hardest gem. Your gemstone jewelry should be the last thing you put on when getting dressed and the first thing you take off at the end of the night. Store your gemstones carefully and they will be enjoyed for generations.
Gemstone and Pearl Care and Enhancement Overview
|Agate||Heated or dyed to improve color.||Basic Gemstone Care.|
|Amber||Heated to improve color and clarity.||Do not use ultrasonic cleaning. Avoid sudden temperature changes, chemicals, perfume, cosmetics, and hairspray.|
|Amethyst||Heated to improve color.||Basic Gemstone Care.|
|Apatite||Heat||Basic Gemstone Care.|
|Aquamarine||Heated to improve color and clarity.||Basic Gemstone Care.|
|Black Diamond||Heated or irradiated to alter color.||Basic Gemstone Care.|
|Black Onyx||Dyed.||Basic Gemstone Care.|
|Black Spinel||None.||Basic Gemstone Care.|
|Blue Topaz||Heated and/or irradiated to alter color. Thermal coated to alter color.||Basic Gemstone Care.|
|Carnelian||Heated to improve color.||Basic Gemstone Care.|
|Chalcedony||Dyed.||Basic Gemstone Care.|
|Chrome Diopside||None||Basic Gemstone Care.|
|Citrine||Heated to improve color.||Basic Gemstone Care.|
|Coral||Coated or impregnated with color less substances to improve surface uniformity or durability. Bleached or dyed to enhance color.||Basic Gemstone Care.|
|Diamond||None.||Basic Gemstone Care.|
|Emerald||Infused to improve clarity and/or color.||Do not use ultrasonic cleaning. Avoid sudden temperature changes, chemicals, perfume, cosmetics, and hairspray.|
|Fire Opal||None.||Do not use ultrasonic cleaning. Avoid sudden temperature changes, chemicals, perfume, cosmetics, and hairspray.|
|Garnet||None.||Avoid sudden temperature changes.|
|Iolite||None.||Do not use ultrasonic cleaning.|
|Kunzite||Heated or irradiated to improve color||Do not use ultrasonice cleaning. Avoid direct sunlight.|
|Labradorite||None.||Basic Gemstone Care.|
|Moonstone||None.||Basic Gemstone Care.|
|Morganite||Heated to improve color and clarity.||Basic Gemstone Care.|
|Opal||Coated to alter surface consistency and durability.|
|Pearl (natural and cultured)||Bleached, dyed, polished and coated.|
|Peridot||None.||Basic Gemstone Care.|
|Prehnite||None||Basic Gemstone Care.|
|Quartz||Green/Lemon: Irradiated to improve color. Smokey: Heated to improve color. Blue: Dyed. Rutilated/Rose/white: None.||Basic Gemstone Care.|
|Ruby||Heated and/or infused to improve color and clarity.||Basic Gemstone Care.|
|Sapphire||Heated and/or infused to improve color and clarity.||Basic Gemstone Care.|
|Spinel||None||Basic Gemstone Care.|
|Tanzanite||Heated to alter color and clarity. Infused to alter color and clarity.||Do not use ultrasonic cleaning and sudden temperature changes.|
|Tourmaline||Irradiated to improve color.||Do not use ultrasonic cleaning and sudden temperature changes.|
|Turquoise||Coated or impregnated with color less substances to improve surface uniformity or durability.||Do not use ultrasonic cleaning. Avoid chemicals, perfume, cosmetics, and hairspray.|
|White Agate||None.||Basic Gemstone Care.|
|White Topaz||None.||Basic Gemstone Care.|