The Codes Used In ACS Gem Descriptions

Jewelry Use Code:

[This code comes right after the name of the gem in the descriptions.]

(J )= Suitable for all jewelry uses; in general, stones with this designation can be used in rings and bracelets; they have hardnesses of 7 or above and good or better toughness. Not all (J) gems can be worn safely in high Tiffany style mounts, or on a 24/7 basis. For that kind of use, gems of hardness 8 and above are recommended.

(J/D) = Suitable for jewelry use, but requiring gentle treatment. The gems with this designator generally can be used in pins, pendants and earrings with no problem. If used in rings or bracelets protective settings are recommended and daily wear is risky. Gems in this group range from 6.5 down to about 5 in hardness and have good to fair toughness.

(C) = Collector stones, not recommended for jewelry use. Due to either softness or fragility setting and/or wearing in any kind of jewelry is risky.
Cutter Code:

[You'll find this code near the end of the description]

This code specifies who cut that particular stone. Not all gems have a specific cutter designation.

BWS = Barbara Smigel, KH = Keith Horst, BB = Barry Bridgestock, BK = Ben Kho, JB = Joel Baskin, ME = Michael Edwards, CR = Carey Robbins

Go to "About ACS" to read more about these cutters

Gem Enhancement Codes:

You'll find these codes in square brackets near the middle in the descriptions, Ex. [Gec: N]

The following codes and definitions are adapted from the American Gem Trade Association's Gemstone Enhancement Manual, Edition 6.1 June, 1997, which is the industry standard for disclosure to consumers.

General Codes:

1) N: Those natural stones which are not currently known to be enhanced by any methods, such as spinel, and therefore can safely be presumed untreated. The symbol "N" is used for these and may also be used in the case of other stones which are sometimes or often treated, which in the particular case are unenhanced. To use this symbol on sapphire, for example, which is generally heated means that the seller certifies that the particular stone was not heated and supplies a document such as an invoice or lab report so stating.


2) E: Those natural stones which are routinely enhanced by traditional methods, the particular stone given this designation, may or may not be enhanced. For example, since most emeralds are oiled an E would indicate such treatment, but would not cover non-traditional methods such as hardened plastic resins (like Opticon) which would require specific enhancement codes such as those listed below. Another example would be the use of E for aquamarine, which in most cases is heated prior to the sale of the rough to remove greenish tints. If the seller knows what specific treatment has been used, then a more specific code should be used.

Specific Codes:

3) Those gemstones for which definite information on standard treatments is known, or to which N and E codes do not apply. because they have been treated in non-traditional ways. Such stones must be disclosed by the appropriate, specific code.

**ACS stones: This site features only natural stones, or those enhanced by only the simplest and most traditional means, so only a very few of the codes below will be seen in ACS gem descriptions, most commonly, H for simple heating, which is so common as to be standard for many gem varieties (citrine, Tanzanite, sapphire and ruby and many tourmalines, for example)**

ASMBL: Assembled Stone - A gem creation of more than piece which can be joined by adhesive or inlayed into metal channels

B: Bleaching - Use of chemicals to lighten or remove a gem's color

C: Coating - Use of surface treatments such as films, lacquers, etc. to provide color or other special effects

D: Dyeing - The introduction of coloring matter into a gem to give it a new color or greater intensity

H: Heating - The use of heat to clarify, change color or create phenomena in gems. Any filler materials which enter the gem as a result must not be visible in fractures at 10x.

I: Impregnating - The use of a colorless resin material within a porous gemstone to enhance stabilty, often vaccuum assisted.

L: Lasering - The use of a laser to drill into a stone and remove or alter an inclusion, refers specifically to diamonds

O: Oiling or Resin Infusion - The intentional filling of surface breaking cavities and cracks in transparent or translucent gems with a colorless oil, wax, resin or man-made unhardened resin.

R: Irradiation - The use some type of radiation process to alter color. Often used in combination with heating treatments.

U : Diffusion - The use of specific chemicals during a high temperature heating process for the purpose of penetrating the surface layer or deeper layers with coloring or star-making chemicals. Such treatment is not generally accepted and stones sold with this enhancement must be specifically labeled as diffused.

W: Waxing/Oiling - The impregnation of colorless wax, oil or paraffin into porous opaque gems to improve appearance.

Want to learn more?

If you have further interest in gem enhancement you can:

Contact the AGTA for an informative brochure entitled: Gemstone Enhancements: What you should know. AGTA, P.O. Box 420643, Dallas, TX 75342-0643. (800) 972-1162

Read the best current reference on the topic: Gemstone Enhancement: History, Science and State of the Art, Second Edition, 1994, by Kurt Nassau, published by Butterworth/Heineman, available from and other retailers.

Artistic Colored Stones has the experience with Faceted Gemstones and Natural Gemstones. We work with all of the Semi Precious Gemstones which refer to all of the colored Gemstones no including the precious gems of Diamond, Sapphire, Ruby and Emerald.


For Inquiries please email or call,

Barry Bridgestock, owner

Artistic Colored Stones

11242 S. Foothills Blvd. Ste. 14

Yuma, AZ 85367