Heated Amethyst & Citrine

November 1998

For Your Staff:Selling Treated Gemstones

Heated Amethyst & Citrine

Amethyst and citrine quartz may be treated with heat to saturate, lighten or otherwise improve the color. Here's how you can discuss it with your customer

This is the sixth in a series of articles Professional Jeweler is presenting on how to explain gemstone enhancements matter-of-factly and positively. Emerald started the series in June, followed by ruby in July, sapphires in August, pearls in September and aquamarine in October.
Amethyst and citrine are similar varieties of the quartz species. The many shades of purple to lavender amethyst and yellow to orange citrine give consumers a lot of choice. One source in Bolivia even produces ametrine, which is amethyst and citrine combined in one gem.

Amethyst and citrine have been cherished since Biblical times; the book of Exodusidentifies amethyst as one of the gems in the High Priest's breastplate, for example.

Years ago, gem experts found controlled heating could alter the color of amethyst and citrine, creating more salable and interesting shades.

Nature produces the same shades of amethyst and citrine that heat-enhancement creates, and it's difficult to determine whether the color is natural or heat-induced. One tell-tale sign: inclusions may expand under controlled heat, causing minute fractures in the stone. Most gemologists agree this is a good way to tell whether quartz has been treated. Still, it's best to tell your customer most amethysts and citrines are heat-enhanced.

How To Introduce Treatments
Explaining to customers how this heat enhancement affects amethyst and citrine is not difficult. Simply relate what happens:

  • Very dark natural amethysts are sometimes heated to produce lighter shades. This makes them more desirable and also allows for consistent colors that can be matched for use in jewelry.
  • Very light purple amethyst can be heated to produce citrine and, to a lesser extent, green quartz.
  • If the amethyst contains color zoning, (a color concentration that conforms to crystallographic growth patterns), these areas have the most dramatic color changes.

Special Care
Amethyst and citrine have a hardness rating of 7 on the Mohs scale and good toughness. The results of heat-treatment on these gems are considered stable and permanent under most conditions, so they require no special care while being worn. But because of the treated gems' susceptibility to heat, they should not be steam-cleaned. Instead, use a toothbrush or soft cleaning cloth.

Also, take care to guard them from heat in the setting process.

Advice for Sales Associates
Learn your store's policies on explaining heat treatment of amethyst and citrine to customers. If you're unsure about what to say, ask the store manager or owner.

Also give your customer a written statement explaining that most amethysts and citrines are heat-enhanced.

Recommended Reading
Gem Identification Made Easyby Antoinette Matlins, Gemstone Press, Woodstock, VT.

GIA's Gem Reference Guide,Gemological Institute of America, Carlsbad, CA.

AGTA Source Directory,1997/1998 Edition (contains the Gem Enhancement Manual),AGTA, Dallas, TX.

AGTA Gemstone Enhancements, What You Should Know,AGTA, Dallas, TX.

 Legal Considerations

The trade considers the colors achieved by heat-treating amethyst and citrine to be stable and permanent under most conditions. However, it's best to disclose the treatment because customers could feel deceived or claim in court they would not have bought the gem had they known it was treated. Note that in the language of the FTC Guides for the Jewelry Industry that follows, heating is listed among the treatments that should be disclosed.

Despite the FTC Guides' mandate, consumers can still sue under state consumer protection laws for unfair and deceptive acts and practices if they feel you didn't explain the treatment properly.

Here's what the FTC Guides pertaining to amethyst and citrine treatment say:

"It is unfair or deceptive to fail to disclose that a gemstone has been treated in any manner that is not permanent or that creates special care requirements, and to fail to disclose that the treatment is not permanent, if such is the case. The following are examples of treatments that should be disclosed because they usually are not permanent or create special care requirements: coating, impregnation, irradiating, heating, use of nuclear bombardment, application of colored or colorless oil or epoxy-like resins, wax, plastic, or glass, surface diffusion, or dyeing. This disclosure may be made at the point of sale, except that disclosure should be made in any solicitation where the product can be purchased without viewing (e.g., direct mail catalogs, on-line services), and in the case of televised shopping programs, on the air. If special care requirements for a gemstone arise because the gemstone has been treated, it is recommended that the seller disclose the special care requirements to the purchaser."

– by Robert Weldon, G.G.




Copyright © 1998 by Bond Communications.


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