Gemstone Treatments

If a gemstone is enhanced that doesn’t mean it’s any less natural. Enhancements are used to highlight the best aspects of gems’ appearance, using various methods to produce brilliant rocks that leave their beholders breathless.


Gemstone treatments

While all gemstones used in ICONIC are naturally formed in the earth, certain gemstones have been enhanced to improve their appearance. Gemstone treatments can be used by a jewelry professional to enhance color, improve appearance, improve durability, color clarity and clarity enhancement, and have been practiced for centuries.

Common gemstone enhancements include heat treating gemstones at high temperatures, filling, irradiation, waxing, dyeing, bleaching, diffusion treatment and cutting and polishing.

Common Gemstone Enhancements

Dyeing gemstone


Dyeing is a treatment technique that involves applying coloring agent chemicals to alter the color of a gemstone. The surface must be porous or fractured in order for the dyeing color to permeate. Chalcedony is one mineral that has been used as a dyeing agent since ancient times, producing colored onyx. For example, lower grade lapis lazuli with lots of white calcite are dyed to achieve the desired royal blue color and improve appearance.


Bleaching is the use of chemicals or other elements (such as light) to lighten a gemstone’s color, improve color clarity or fade dark spots. Both pearls and jade are very often bleached to improve appearance. Even to the trained eye, gems that have undergone this treatment are virtually undetectable.


Coating is the application of lacquer or some other type of coloring agent to a gems’ surface in order to improve appearance and enhance color.


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Fractures are natural to gemstones but can lower their value. Filling gemstones is a treatment that improves the appearance of stones using materials such as glass, plastic, wax or oil to fill cavities or fractures in a gemstone’s surface. This technique reduces the visibility of imperfections, as well as adding weight to the gemstone. Stone filling oil is often used to fill fissures found naturally occurring in emeralds and to enhance clarity. A treated emerald is known as ‘oiled’ emerald. Other two gemstones that are commonly treated with fracture filling are diamonds and rubies.

Heat Treatment

The most common method to improve color clarity is temperature heat treatment. Heat treatment is a treatment process used to lighten, darken or even change the natural color of gemstones. Heating uses high temperatures to enhance the color and clarity of a gemstone. and improve appearance. This permanent heat enhancement treatment is often used with gemstones such as aquamarine, topaz, ruby and sapphire. Heating can also improve the clarity of some gemstones. For example, heating aquamarine can get rid of the yellow and green hue, leaving a bluer gem as a result. Heat treating sapphire to improve a sapphire’s color, remove color zoning, and improve its clarity. Heat treated ruby can intensify a ruby’s natural color and also improve ruby clarity by removing or reducing inclusions and making them less visible.

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Diffusion treatment is used to improve and change the color of colorless or pale gems by applying chemicals to the surface and heating the gemstone. Ruby and sapphire are commonly treated this way. By applying the right chemical on the surface and then heating the gemstones, the chemicals are able to travel into the crystal structure, creating color that is not there before the treatment. Deep red ruby and vivid color sapphire can be produced this way. The value for the treated gemstone will be much less than the naturally colorful ones. Diffusion treatment may only penetrate the outermost surface of the gem. In this case, when it is chipped or scratched, the original color may be exposed.


Irradiation is a gem treatment that exposes a gemstone to artificial radiation for color enhancement purposes and improve appearance. Irradiation is sometimes followed by heating in order to permanently alter a gem coloring, as in the case of blue topaz. Virtually all blue topaz in the market are subjected to gemstone irradiation so as to turn this raw precious stones’ color from white to blue. Other gems that are sometimes radiated include diamond, kunzite, tourmaline, and pearl. Irradiated gemstones like color enhanced diamonds are hard to detect so much so that only gemologists in a laboratory with sophisticated equipment can do that.

Frequently Asked Questions

A filled gemstone or filling a gemstone is a very general term which can cover a multitude of different treatments from merely oiling the stone to impregnating fractures or inclusions with resin to improve durability and clarity enhancement. There is a lot of debate about this practice with purists believing the resin should not be used.
Natural rubies in their pure state are unheated. However, natural enhanced rubies undergo a heat treatment process to try and improve their appearance. They are still rubies, although there is some debate regarding whether they are natural because heating upgrades the colour and shine.
Thermal enhancement is a treatment technique applying heat treatment to gemstones such as rubies and sapphires, to enhance their color and improve their clarity. The minerals are changed from their natural rough state to be used in fine gemstone jewelry.
A treated stone is still a genuine gemstone, but it has been enhanced via a treatment procedure to improve its appearance and increase its value. Common gemstone treatments include high temperature heat treatment, surface stone coating, staining and irradiation.
Stones you can wear every day without worrying too much are diamonds, topaz, ruby and sapphire. The gemstones that need to be worn more carefully due to their hardness, durability and wearability are Pearls, Opals, Jades, Aquamarines, and Onyx.
Gemstone treatment is the process of changing or enhancing the appearance of natural gemstones. Usually it’s used to change the color to one that market desires or increase the clarity of gemstone. Sometimes it involves combination treatments which improve the appearance. The price for the treated gemstone is more affordable than an untreated natural gem. 
Common heat treated gemstones include aquamarine, tanzanite, amethyst, citrine, blue topaz, blue zircon, tourmaline, rubies and sapphires.
A gemstone is formed within the earth naturally below the surface. Gems can be brought to the surface through mining and through naturally occurring earth processes such as faulting, folding, uplifts, volcanic activity.
Common heat-treated gems include amber, ruby, amethyst, tourmaline, aquamarine, citrine, sapphire, tanzanite, and topaz. High Heat High Temperature (HPHT) treatment processes are used for brownish color diamonds to transform them into colourless diamonds. This type of diamond enhancement can even turn their colour to blue, orange or yellow.
Non-treated gems include Spinal (full range of colors), Orange Spessartite, Rhodolite Garnet,  Tourmaline and Peridot.
Heating gemstone treatments actually increase and improve durability of gems in terms of color stability and wearability.
If you study the surface coatings and color of a gem and notice parts where color is highly concentrated then it is most likely that the stone has been dyed. A commonly dyed crystal is amethyst and unfortunately dyed crystals lose their overall value.
A sapphire that has been exposed to heat treatments is considered acceptable by the jewelry industry, although a sapphire that has no evidence of heat treatment increases its value.