Gemstone Treatment Guide

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, fracture filling, irradiation, waxing, dyeing, bleaching, diffusion treatment and cutting and polishing using equipment such as gem cutters.

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 of gem materials 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 for many gems since ancient times, producing colored onyx. For example, lower grade lapis lazuli with lots of white calcite are dyed to achieve the desired royal or pale blue color and improve appearance.


Bleaching is one of many gem treatments that use chemicals or other elements (such as strong light elements) to lighten a gemstone’s color, improve color clarity or fade dark spots. Both pearls and jade are very often bleached to improve appearance of many gems. Even to the trained eye, gem crystals 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.


heat treatment

Fractures occur naturally in gemstones but surface reaching fractures can lower their value. Fracture filling, one of many gemstone treatments, improves the appearance of stones using materials such as leaded 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 gem materials. Stone fracture 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. Two other gemstones that are commonly treated with surface reaching fractures filling are fancy color diamonds and rubies.

Heat Treatment

The most common method to improve color clarity is temperature heat treatment. Heat treatment is a gemstone enhancement 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 component and green color, leaving a bluer gem as a result. Heat treating blue sapphire to improve a sapphire’s deep blue 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 on a particular gemstone.

heat treated


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 of such stones, creating color that is not there before the treatment. Deep red ruby and vivid color sapphire are some examples of treated stones that 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 materials. In this case, when it is chipped or scratched, the original color may be exposed.


Irradiation is a gem treatment technique that exposes a gemstone to artificial radiation for color enhancement purposes and to improve appearance. Irradiation is sometimes followed by heating in order to permanently alter gem coloring, as in the case of natural blue topaz. Virtually all blue topaz in the market are subjected to gemstone irradiation so as to turn this raw precious stone’s color from white to blue. Gems other than irradiated blue topaz that are sometimes subject to radiation treatment include colored diamonds, kunzites, tourmalines, and cultured pearls. Irradiated gem materials like color enhanced diamonds are hard to detect so much so that only gemologists inside the gem laboratories of a gemological institute with sophisticated equipment can identify irradiated gems inside their gem labs.

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 surface reaching fractures or inclusions with resin to improve durability and clarity enhancement of the gem material. There is a lot of debate about this practice with purists believing the resin should not be used because it devalues the finished gem.
Natural rubies in their pure state are unheated. However, naturally-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 gemstone’s color and shine.
Thermal enhancement is a treatment technique applying heat treatment to gemstones such as rubies and blue 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 jewelry repair procedures to improve its appearance and increase its value. Common treatments of gemstone include high temperature heat treatment, surface stone coating, staining and irradiation. They can also be subject to combination treatments to improve their clarity.
Stones you can wear every day without worrying too much are diamonds, colorless topaz, , yellow beryl, ruby and sapphire. The gemstones that need to be worn more carefully due to their hardness, durability and wearability are Pearls, Opals, Jades, Aquamarines, Onyx, Green Quartz and other gems.
Gemstone treatment is the process of changing or enhancing the appearance of the vast majority of natural gemstones, such as smoky quartz. Usually it’s used to change the color to one that market desires or increase the apparent clarity of gemstone. Sometimes it involves combination of common 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 naturally just below the earth’s surface. Colored gemstones 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, star ruby with a pink color, 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 colorless diamonds. This type of diamond enhancement can even turn their color to blue, orange or yellow. There are also many kinds of irradiated gemstones.
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 colored gemstones in terms of color stability and wearability.
If you study the surface coatings and color of a gem material bought in a gem trade and notice parts where color is highly concentrated, then it is most likely that the stone has been dyed. A commonly dyed gemstone 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 or gem trade, although a sapphire that has no evidence of heat treatment has a higher value.
Laser drilling is one of many gemstone enhancements that aim to increase a diamond’s clarity. The process involves drilling tiny holes on the diamond’s surface, usually thinner than a hair. The primary reason that a diamond is laser drilled is to remove black spots.