Gemstone Enhancement Guide

Gemstone Enhancement

Gemstone enhancement has been defined by the American Gem Trade Association as "any traditional enhancement process other than cutting and polishing that improves the appearance, durability or availability of a gemstone." Unlike diamonds, natural gemstones are commonly enhanced. Nearly all loose gemstones on the market as well as those already set in fine Gemstone Jewellery have been enhanced. The jewellery industry widely accepts a variety of gemstone enhancement methods, the most common of which are listed below with their industry notation.

H   Heating

Exposing a gemstone to heat in order to enhance the colour or clarity of a gemstone. Heat treatment alters the stone's basic chemical makeup. By heating the stone to intense temperatures, the stone's internal inclusions dissolve and reform, thus enhancing the gemstone's colour as well as its clarity. Heat treatment has been a standard enhancement method and heat treated gemstones are considered acceptable by the gemstone market since this particular enhancement treatment can occur naturally while the gemstone resides underground. It is extremely rare to find a gemstone on the market which has not been heat enhanced. This type of enhancement is permanent.

R   Irradiation

Applying radiation in order to enhance the colour of a gemstone by changing the electron dispersion within the stone's crystalline structure. The enhancement is typically combined with heat treatment. The irradiation process can cause the gemstone to turn from colorless to a rainbow of colors. This enhancement is usually permanent. In rare cases the enhancement will fade over time.

D   Dyeing

Applying colouring matter to a gemstone in order to enhance its colour or improve uniformity. This enhancement is usually permanent. In rare cases the dye will fade over time.

B   Bleaching

Using light, heat, chemicals or other materials to lighten colour, improve colour consistency, or remove colour.

F, I, O   Filling, Impregnation or Oil/Resin Infusion

Filling a gemstone's internal gaps, cracks, fissures, or other surface-breaking cavities with a colorless material such as plastic, glass, oil, resin, wax, in order to improve its appearance and/or weight. All of these techniques have been practiced for centuries.

C   Coating

Using lacquer, enamel, ink, or films to the surface of a gemstone. This can improve appearance, durability and/or colour.

L   Lasering

Using a laser to reach, modify and/or remove inclusions and blemishes.

Common Gemstones and Enhancement Methods

The following enhancement methods are widely used and accepted in the international gemstone industry: