Gemstone Enhancement with the DCLA

The DCLA is committed to offering industry-leading coloured gemstones. Our gemologists take seriously their duty to provide you with the highest level of education and quality.

It is widely accepted in the jewellery industry that gemstones are enhanced to improve their lasting power and beauty. By allowing gemstones to undergo treatment, you ensure that your gemstones remain within a reasonable price range as perfect, untreated gemstones can be worth exorbitant amounts. To the naked eye, most enhancements are invisible and require no care beyond the initial treatment. Universally used and unnoticeable, treated gemstones ensure that the full beauty of the gemstone is displayed at a low cost.

Please note that our certified diamonds do not undergo treatment or enhancement.

What is the gemstone enhancement process?

While there are dozens of methods for enhancing gemstone colour, below we detail a few of the most common. If you’d like more information, feel free to contact one of our gemologists.

Heat Treatment

Heat treatment is considered the most natural of all enhancements because it essentially finishes the process that began in the ground. Applying high heat to the coloured gemstone causes the inner workings of the stone to reform and create brighter colour with greater clarity. This process cannot be reversed because the colour and renewed clarity is a natural part of the gemstone.


Some of the more dramatic black gemstones are good examples of stones that have been dyed. Dyeing is simply the process by which extra colour is added to the gemstone to enhance the colour beyond what is possible by nature.


There are many different terms for this process, but the end process is always injecting the coloured gemstone with a foreign substance to improve colour or clarity. Materials common to this process include glass, wax, oil, and resin. This is a very old enhancement process that originated centuries ago, and continues to this day.


Irradiation is the process of exposing gemstones to subatomic particles or other radioactive material. Irradiation is usually paired with the heating treatment to create better, stronger colours. Although it sounds dangerous, this process is carefully monitored to ensure there is no danger to consumers.


Originating 200 years ago, coating is the process of painting a lacquer on the surface of the gem to improve the outer appearance. This can affect the colour dramatically. Coatings have a dubious reputation in the diamond community because occasionally unscrupulous dealers would paint off-coloured stones to trick a buyer. However, within the gemstone industry, coating is an accepted way to enhance colour without changing the makeup of the stone.


Bleaching is only appropriate for organic gemstones such as pearls. It brightens the colour. When this process is applied, it is usually impossible to detect.


This is a process that is usually reserved for emeralds. After the stone is mined, it is immersed in a vat of oil that is used as lubricant during the cutting process. Because the cut diamond has not been sealed against the elements, oil seeps into the stone and fills inclusions. Bear in mind that while this is a popular and widespread treatment for emeralds, not every emerald is oiled. Emeralds that have not been oiled usually command huge prices because of their excellence.

The Future of Gemstone Enhancements

As technologies develop and evolve, there will continually be new ways to enhance coloured gemstones. The DCLA remains at the forefront of detecting these techniques and works with the industry to make sure we always offer our clients the best information.

Basic Gemstone Care

Gemstones, while hardy and able to withstand certain levels of pressure, do require some maintenance to ensure they retain their sparkle. Depending on the variety, your gemstone may require caution around household cleaning products, or care in extreme temperatures. You should speak to our gemologists about the specific care for your coloured gemstones, but below is a basic guide to get you started.


There are a lot of jewellery cleaners on the market, so it’s important to choose wisely. Look for one that is non-abrasive and will be gentle, yet effective at getting off any dirt. After using the cleaner, gently brush your gemstone jewellery with a soft cloth to remove anything that remains.


It is important to keep your gemstone jewellery in a separate cushioned box or soft cloth to ensure that no wear and tear occurs during storage. Gemstones are able to easily scratch precious metals like gold, silver, and platinum if not stored correctly.


Even diamonds, the hardest natural substance in the world, are susceptible to wear and tear.  Therefore, it is even more important to be careful with gemstones. Scratches, harsh chemicals, and direct hits to the stone will leave their mark over time and you may be shocked to realise that one day the shine has diminished. Treat your gemstone jewellery with care and protect them from harsh substances. With the right care, they will become a precious heirloom.