ColourWise (Calibration)

Treatments & Enhancements

What is the distinction between a gemstone treatment and a gemstone enhancement?

A gemstone treatment refers to any procedure that is performed on a gemstone, while a gemstone enhancement is something, usually a treatment that improves or enhances the gemstone making it more saleable, valuable or durable.

Common treatments include:

Treatments & Enhancements


In an ideal world, the seller of a gemstone would freely disclose to the buyer that the gemstone has undergone some form of treatment or enhancement and this information would be passed down through a ‘chain of warranties’ to the end user.

In reality, the goal of every gemstone treater is to profit from his work and the longer the treatment goes undisclosed and undetected, the greater his financial rewards. While many may find this morally and ethically reprehensible, the very fact that the science of gemmology is inextricably intertwinned with the buying and selling of gemstones makes it unavoidable. Certainly one can argue that if a treatment is permanent, irreversible and universally practiced, it does not need to be disclosed but what about the treatments that are impermanent and unstable? While the International Jewellery Confederation (CIBJO), The International Coloured Gemstone Association (ICA), and The American Gem Trade Association (AGTA) have all issued guidelines regarding the disclosure of known and detectable treatments and enhancements to their members, they are often difficult to identify without the use of highly sophisticated equipment or submitting them to a recognized laboratory. This adds a significant cost that many dealers or jewellers are unprepared to shoulder unless the ensuing laboratory report adds real or perceived value to the gemstone.


Since every gemstone is unique and different, it is impossible to state categorically whether a treatment is permanent and stable. Therefore any references to permanency and stability, merely reflect what is generally accepted within the gemmological community, the trade, and by the various trade organizations.


The role of a jewellery appraiser is not to set prices, merely to reflect the prevailing market conditions. To achieve this he must not only draw on his own experience and knowledge but also closely monitor what is happening in the trade by attending gem shows, trade conferences and subscribing to industry publications, and price guides. GemGuide is a well-respected wholesale price guide published by Gemworld International Inc. that covers a wide range of diamonds and gemstones and includes price adjustments for treated emeralds, rubies and clarity enhanced diamonds. They also include pricing grids for untreated Burmese and Mozambique rubies, untreated Burmese blue sapphires, and unenhanced padparadscha, pink, purple and yellow sapphires.