Gemstone Treatments Guide gem treatments explained

Gemstone Treatments

Just as wood furniture needs to be lacquered, so to gemstones require finishing before they are ready to be sold. Critical as good cutting and polishing, treatments have become an integral part of the modern gemstone industry. Akin to aging fine wine, most of the techniques used simply facilitate the beautiful end results of the earth’s natural processes.
While these treatments are taken as commonplace within the industry the general public's awareness has been much lower. This page provides clear answers to common treatment questions. If you need any further information on treatments, please access the guidelines provided by the U.S. Federal Trade Commission.
Is the use of treatments globally accepted?
Yes, with close to 99% of the more popular gem types treated, all permanent techniques are universally accepted. As the majority of gemstones traded internationally have undergone some form of treatment, always assume treatment when purchasing gemstones. In fact, some techniques such as heating are centuries old - in all likelihood your grandmother’s ruby ring has been heat-treated!
Are all the treatments used permanent?
Affordable Gems and Jewelry, with the exception of Emeralds that are treated with Colorless Oil or Polymers, only knowingly accepts treatments that are permanent and stable.
Why are natural gemstones treated?
Most commonly used to improve the color or appearance of the finished product, some gemstones simply would not exist in salable quantities without treatment. For example, heating greenish brown Zoisite to 600 degrees Celsius produces the currently popular vibrant violet-blue Tanzanite. No heating, no Tanzanite! Please note that the term “natural gemstones” refers to those formed in the earth, whether or not they have been treated after mining - this is in distinct contrast to “lab”, “man made” or “synthetic” gems.
Does treatment affect a gem’s value?
At Affordable Gems and Jewelry we see no difference in the value of treated and untreated colored gemstones. While some dealers claim that untreated quality gems should receive a higher market value, Affordable Gems and Jewelry prefers to stick to the standard assessments of clarity, color, cut and origin. This means that even within the gem types where treatment is commonplace, we offer a large amount of untreated gemstones, yet we make no distinction in these listings. Why is this? The most common treatment technique is heating. This technique is so common with Rubies and Sapphires that most gemologists would tell you they are “probably heat treated”. But saying that something is “probably treated” doesn't sound very professional? The difficulty here is that because the procedure so closely resembles what happens in nature, a gemologist can't always tell if they have been treated. While microscopic examination will occasionally reveal an inclusion that burst during heating, there is often no way to tell if the material was treated. Another example is Aquamarine. When properly heated, Aquamarine loses its green tint becoming a pure blue. As this is identical to what happens in nature, there is no way of telling if it was done after mining.
What gemstones are usually treated and how?
The following table provides information on the treatments used for specific types, their purpose and frequency:

Gemstone	Treatment	Explanation
Agate	Dyed or Heated	Used to alter color, these treatments are usually applied.
Amazonite	Colorless Wax, Oil Hardened Resin	Used in improve the gems' appearance, these treatments are usually applied.
Amethyst	Heated	Used to lighten color and/or to remove smokiness, this treatment is only occasionally applied.
Aquamarine	Heated	Used to remove yellow components to produce a purer blue color with fewer yellow/green undertones this treatment is occasionally applied.
Citrine	Heated	Usually applied, this treatment alters or improves color.
Cornelian	Heated	Usually applied, this treatment produces color.
Diamond (Enhanced)	Irradiated (Diamonds subjected to this treatment DO NOT become radioactive. This process exactly duplicates the natural exposure of gem crystals to radioactive elements during their formation. All Enhanced Diamonds sold at Affordable Gems and Jewelry are irradiated in the U.S. to certified international standards.)	Used to improve color intensity or to produce unique colors, this treatment is always applied for enhanced Diamonds.
Emerald	Colorless Oil or Polymers	Usually applied, this treatment improves the appearance. If properly cared for this treatment is permanent. Click here to learn simple tips to keep your Emeralds looking great.
Morganite	Heated	Commonly used, this treatment eliminates yellow overtones.
Opal (Doublet)	Assembled Product	Always used, this treatment improves durability and/or color.
Pearl (Cultured)	Bleached, Dyed or Chemically Enhanced	Usually used, these treatments improve color and uniformity.
Prasiolite	Heated	This treatment improves color and appearance and is usually applied.
Quartz	Heated	Usually applied, this treatment improves color.
Ruby	Heated	This treatment improves color and appearance and is usually applied.
Sapphire	Heated	Usually applied, this treatment produces, intensifies or lightens color and/or improves color uniformity and appearance.
Star Sapphire (Diffusion)	Diffusion	Always applied for this type, this treatment produces an artificial star on a natural stone.
Tanzanite	Heated	Always applied, this treatment produces the violet-blue color for which the stone is known.
Topaz	Heated	Used to improve color intensity or to produce unique colors, this treatment is usually applied.
Tourmaline	Heated	Used to improve color intensity, this treatment is commonly utilized for blue green colors and only rarely applied for other color hues.
Zircon (Blue & White)	Heated	Used to improve color, this treatment is always applied.