AGTA Gemstone enhancment chart

The American Gem Trade Association published a gemstone enhancement information chart.
This manual sets forth proper methods to comply with the FTC Guides. With the exception of the normal fashioning (cutting and polishing) of a diamond or other gemstones, it is the seller's responsability at the time of sale to provide all informations pertinent to the enhancement of a natural gemstone. If the stone is man-made, it is also the seller's responsabiliy to disclose the fact. This information is required by the Federal Trade Comission (FTC).

Failure to identify and announce enhancement of natural gemstones, when present,
is an unfair trade practice.

This manual, provides an easy to understand shorthand system for labeling. Any treatment process other than cutting and polishing that improves the appearance, durability, or availability of a gemstone is an enhancement.

Category of those which are not enhanced
 N Not enhanced. The stone has received no enhancement and the seller will provide a guarantee that there has been none.
Category of those which are enhanced
 E Indicates that the gemstone is routinely enhanced. Possible are one or several enhancements. They will be specified with the following codes in the category of specific enhancment.
Category of specific enhancment
 B Bleaching: The use of chemicals or other agents to lighten or remove a gemstone's color.
 C Coating: The use of such surface enhancements as laquering, 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: As a by-product of heat enhancement, the presence of solidified borax or similar colorless substances which are visible under properly illuminated 10X magnification.
 G Gamma/Electron Irradiation: The use of gamma and/or electron bombardement to alter a gemstone's color; may be followed by a heating process.
 H Heating: The use of heat to effect desired alteration of color, clarity, and/or phenomena. (Residue of foreign substances in open fractures is not visible under properly illuminated 10X magnification.)
 I Infilling: The intentional filling of surface breaking cavities or fractures usually with glass, plastic, opticon with hardeners and/or hardened foreign substances to improve durability, appearance and/or add weight.
 L Lasering: The use of laser and chemicals to reach and alter inclusions in diamonds.
 O Oiling/Resin Infusion: The intentional filling of surface breaking cavities with a colorless oil, wax, natural resin, or unhardened man-made material. (Oil, man-made resin, cedar wood oil, Canada balsam, paraffin, etc.)
 R Irradiation: The use of neutron, requiring an environmental safety release from the Nuclear Regulatory Commission, with the combination of any other bombardement and/or heat treatment to alter a gemstone's color.
 S Bonding: The use of colorless bonding agents (commonly plastic) within a porous gemstone to give it durability and improved appearance.
 U Diffusion: The use of chemicals in conjunction with high temperatures to produce color and/or asterism-producing inclusions.
 W Waxing/Oiling: The impregnation of a colorless wax, parafin and oil in porous opaque gemstones to improve appearance.
Category of synthetic stones
SYNSynthetic materials. The name synthetic must be accompanied by a specific reference to the actual composition.
IMITImitations, product-simulants, subsitutes. Trade names used to promote various simulant products in these category must be accompanied by a specific reference to the actual composition of the simulant.
ASBLAssembled materials, composite, doublets, triplets. Tag for products of multiple layers or combinations of manufactured and/or natural materials fused, bonded or otherwise joined together to increase stability and/or to imitate the appearence of a natural gemstone, create a unique design or generate unusal color combinations.

Anyone who is uncertain abour these requirements may write to the
AMERICAN GEM TRADE ASSOCIATION
PO Box 420643
Dallas Texas 75342-0643
USA

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