1. Heat Treatment
Heat treatment is the most common treatment technique used on gemstones. Reference to heat treatment of gems is found in gemmological literature dating back thousands of years. Heat treated gems are stable and the treatment is usually permanent. The vast majority of gemstones (above 90%) are heated to alter their color. In ruby and sapphire the treatment is often performed to improve color and clarity.
Before Heat Treatment
After Heat Treatment
Irradiation refers to the use of neutrons, gamma, and/or electron bombardment to alter a gemstone’s color. The irradiation stage of the process is then usually followed by a heating phase to effect the change. Blue topaz is typically produced by irradiation
3. Diffusion Treatment
This treatment is usually done to improve the colour and appearance of lightly coloured sapphires. The sapphires are heated to extremely high temperatures while adding certain elements such as beryllium, chromium and/or titanium to the process.
4. Clarity enhancement/ Fracture filling
Clarity enhancement/ Fracture filling refers to the filling of surface breaking fractures or fissures with colorless glass, resin or similar substance. This process is done to improve durability, color and transparency. This treatment is usually done on emeralds, rubies and sapphires.