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Treatments for Gemstones

As humans we are always striving to achieve beauty and perfection whether through cosmetic surgery or natural treatments. Some treatments can last forever while others just give us a boost for a short time.

Similarly, gemstones can be treated using many different methods to enhance their natural beauty. The very first documentation of gemstone treatment was presented thousands of years ago by Pliny the Elder, commander of the early Roman Empire, renowned author, naturalist and philosopher. So the process of treating and enhancing precious gems is an ancient tradition that dates back thousands of years which is still practiced today.

Without gemstone enhancements many of the most popular gemstone types would not be available today or even exist, such a London Topaz. It may be hard to imagine, but the rainbow of available gemstones we take for granted today wouldn’t exist without various forms of treatments.

It is common knowledge within the industry that the majority of emeralds, rubies and sapphires are in some way enhanced or treated. Only the very pure, perfectly coloured and flawless can escape any type of enhancement, and this is reflected in their record-breaking prices.

Whilst heat treatment is globally the most common and widely accepted treatment within the gemstone trade, there are plenty of other common applications to both crystalline and organic gem materials:

  • Surface Modification

  • Fracture/Cavity Filling

  • Heat Treatment

  • Diffusion

  • Impregnation

  • Irradiation

  • Laser Drilling

  • Oiling

  • Dyeing

  • Bleaching

The most common treatments for the ‘big three’ are heat treatment with or without irradiation, oiling, diffusion and cavity and fracture-filling. Of these, heating and oiling are the most widespread and when applied correctly and disclosed are acceptable enhancements. Cavity and fracture filling are, by the nature of the treatment, applied to lower quality stones. They enhance material that would otherwise be extremely fractured and are acceptable but without the correct care the effects don’t last forever so special care must be taken when cleaning jewels subjected to these treatments. Diffusion that alters the colour of a stone at its crystal lattice level. This can penetrate the whole stone or just at surface level but must be disclosed as it lowers the value of the stone and is very hard to detect. Often if a stone of value is suspected to have been subjected to this it is usually referred to a laboratory for confirmation.

Let’s take a close look at the most common treatments and how to spot them!