Gemstone Treatments

Typically Accepted Gemstone Treatments:

Just as wood furniture needs to be finished, gemstones require finishing before they are ready to be sold. As critical as good cutting and polishing, treatments have become an integral part of the modern gemstone industry. Similar to aging a 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 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 email support@artisticcarver.com or alternatively 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.

Are all the treatments used permanent? Most treatments are permanent with the exception of Emeralds that are treated with Colorless Oil or Polymers.

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 ArtisticCarver.com 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, ArtisticCarver.com prefers to stick to the standard assessments of clarity, color, cut & carat as well as origin. This means that even within the gem types where treatment is commonplace, we also have 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 Ruby 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 when this heating took place or 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 to 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.

CARNELIAN

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 ArtisticCarver.com 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.

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, intensified or lightened 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.

Disclosure of Treatment:

The majority of gemstones traded internationally have undergone some form of treatment. You should always assume treatment when purchasing gemstones. We hope the above has clearly presented the facts surrounding the treatment of gemstones.