There are many methods of enhancing colored gemstones. We describe the most common enhancements below. 

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. The enhanced color and/or clarity of heat-treated gemstones is permanent.


Infusion

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.


Coating

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.


Bleaching

The application of chemicals or other elements to lighten or enhance color consistency.


Dyeing

The act of adding coloring agents so that they permeate a colored gemstone to enhance or alter color.


Irradiation

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.