ENHANCEMENT: Any traditional process other than cutting and polishing that improves the appearance (color/clarity/phenomena), durability or availability of a gemstone.

A gemstone enhancement is considered permanent as long as the effect of the enhancement does not change under normal wear, cutting, repair, cleaning or display conditions. If a gemstone enhancement is not permanent, appropriate disclosure is required.

With respect to treatment, all natural gemstones can be divided into two basic categories:

  1. Those which are not enhanced. The "N" symbol appears on the chart only for natural gemstones which are not currently known to be enhanced (Alexandrite, Garnet, etc.). However, the "N" symbol can also be used for other natural gemstones in the event that a gemstone has received no enhancement and the seller will provide a guarantee that there has been none. That gemstone must be accompanied by a commercial document, such as an invoice, memorandum and/or a laboratory report, to support the fact that the gemstone is not enhanced.
  2. Those treatment processes not covered under the "N" symbol are addressed in a specific manner below. Since many enhancements are difficult or impractical to prove definitively, the approach taken in this manual is, unless otherwise indicated, to assume that such traditional enhancement has been done to that particular gemstone. This assumption has been made in order to protect both the seller and the consumer. For example, Ruby "F." The surface cavities are filled with a foreign matter such as glass. Within the industry, this gemstone must be labeled with the letter "F." This information must also be provided to the consuming public in writing using plain language. Abbreviations and codes are not sufficient.

NOTE: Multiple enhancement techniques are sometimes applied to the same material.
All treatments must be listed. Example: Diamond "LF" (Lasering and Filling).

Defined below are the specific enhancement codes and designations to be used in the GEMSTONE INFORMATION CHART.

SYMBOLS FOR SPECIFIC FORMS OF ENHANCEMENTS:

N -  Natural: No modification (or currently has no known modification process).

B - Bleaching: The use of heat, light and/or other agents to lighten or remove a gemstone's color.

C - Coating: The use of such surface enhancements as lacquering, enameling, inking, foiling or sputtering of films to improve appearance, provide color or add other special effects.

D - Dyeing: The introduction of coloring matter into a gemstone to give it new color, intensify present color or improve color uniformity.

F - Filling: The filling of surface-breaking cavities or fissures with colorless glass, plastic, solidified borax or similar substances. This process may improve durability, appearance and/or add weight.

H - Heating: The use of heat to effect desired alteration of color, clarity and/or phenomena. If residue of foreign substances in open fissures is visible under properly illuminated 10X magnification, H F should be used.

HP - Heating and Pressure: The use of heat and pressure combined to effect desired alterations of color, clarity and/or phenomena.

I - Impregnation: The impregnation of a porous gemstone with a colorless agent (usually plastic) to improve durability and appearance.

L - Lasering: The use of a laser and chemicals to reach and alter inclusions in gemstones, usually diamonds.

O - Oiling/Resin Infusion: The filling of surface-breaking fissures with colorless oil, wax, resin or other colorless substances, except glass or plastic, to improve the gemstone's appearance.

R - Irradiation: The use of neutrons, gamma rays or beta particles (high energy electrons) to alter a gemstone's color. The irradiation may be followed by a heating process.

U - Diffusion: The use of chemicals in conjunction with high temperatures to produce ARTIFICIAL color change and/or asterism-producing inclusions. Note: It is a violation of the FTC Guides to fail to disclose diffusion on gemstones in advertising, promotional literature or commercial documents. Suggested methods of disclosure are: "(Gemstone): chemically colored (Color) by diffusion." Example: "Sapphire: chemically colored blue by diffusion." If the color of the diffused gemstone does not permeate the entire stone, then the following statement must also appear: "Although the color induced in diffusion treated gemstones is permanent, it does not permeate the entire gemstone; therefore, recutting or repolishing is not recommended."

W - Waxing/Oiling: The impregnation of a colorless wax, paraffin or oil in porous opaque or translucent gemstones to improve appearance.

The above disclosure language must be printed in a type-size and location so as to be conspicuous.

Designations are based on a consensus of opinion rather than any available documentation.