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Gemstone Enhancement
It may upset some purists to know that almost all the gemstones on the market, both loose and those set in jewellery, have been enhanced in some way. This is a common practice, however, and widely accepted by the industry. The American Gem Trade Association currently defines gemstone enhancement as 'any traditional enhancement process other than cutting and polishing that improves the appearance, durability or availability of a gemstone.' The most common methods are listed below.


Almost all the gemstones in the marketplace have been exposed to heat to improve their colour or clarity, often as a combined effect. Applying heat can modify the stone's chemical makeup, as well as causing its inclusions to dissolve or change, permanently enhancing not just its clarity but also its colour. The reason why the international jewellery industry widely accepts such a method is that gemstones located deep below the earth's surface are constantly exposed to heat and, therefore, this process may occur naturally.


Exposing a gemstone to radiation is another way of permanently intensifying its natural colour, and this method is often applied in combination with heat treatment. This process alters the dispersion of electrons within the gemstone and, in some cases, can turn a colourless gemstone into one that exhibits a bright rainbow of colours. While this enhancement method has been known to fade with time, reports of such incidents have been rare.


This is the process of brightening a gemstone's colour, or evening it out, through the application of permanent dye to the stone. The effect is almost always permanent, with only a few rare cases of the enhancement fading over time.


This is when a gemstone's colour is enhanced, lightened, or removed using elements such as light, heat and chemicals.

Filling, Impregnation or Oil/Resin Infusion

An ancient practice that has been refined and modernised over the years, this practice involves artificially filling in a gemstone's natural cavities with colourless glass, plastic, wax, oil or resin to improve both its weight and appearance.


Some gemstones are coated with lacquer, enamel, ink or films to enhance their appearance and/or strength.


This technique uses laser technology to repair or remove a gemstone’s internal inclusions and/or external blemishes.

Common Enhancement Methods Applied To Gemstones

Gemstone Enhancement Method
Amythyst Usually heated to improve color
Aquamarine Usually heated to improve color and appearance
Black Onyx Dyed
Blue Topaz Usually heated/irradiated to enhance blue color
Citrine Usually heated/irradiated to enhance color
Coral Commonly bleached
Diamond None
Emerald Oiled with colorless oil
Garnet None
Jade Impregnated with colorless wax
Lapis Lazuli Impregnated with colorless wax or oil
Opal Coated to improve surface strength and appearance
Pearls Commonly bleached, dyed, polished or coated to improve color and appearance
Peridot None
Ruby Usually heated/infused to enhance color and clarity
Sapphire Usually heated/infused to enhance color and clarity
Tanzanite Usually heated/infused to enhance color and clarity
Tourmaline Commonly irradiated to intensify pink, red or purple color
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