Even despite the fact that most gemstones are incredibly beautiful by nature, there are still tricks which help to improve colour and clarity. Among the methods of treatment applied to gemstones the accepted trade methods are those which change the colour of the gemstone permanently. Speaking about coloured gemstones, most of them are treated and this is an absolutely legitimate practice on condition that buyers is provided with detailed information and is fully aware of what they are buying.

With this post I’m going to look into the most widely accepted in the trade today methods, the knowledge of which will help you to feel safe and take clever decisions when buying a gemstone. Let’s start with the heat treatment and learn what exactly it is and in what way it influence gems.

Heat treatment is a type of enhancement which produces the magical effect turning a colourless gemstone into something amazing. This technique is a natural continuation of the process occurring in the earth when the stone was formed. High heat (approximately 1600 Centigrade) makes natural inclusions, chemical elements, and other impurities to reform and change the colour of the stone forever. Without this technique there would be hardly enough affordable gemstones.

Gemstones that are commonly heated include amethyst, citrine, ametrine, aquamarine, tourmaline, topaz, light green tourmaline, ruby, sapphire, tanzanite, and blue zircon. If to apply heat treatment to amethyst, for instance, it will change the colour from pale to yellow, thus will be sold as citrine, tanzanite will become of a more desirable blue shade and ruby of  better colour of red.

Meanwhile, it is still possible to detect heat treatment using a microscope since modifications of natural inclusions such as the destruction of gas or fluid inclusions or the dissolving of mineral inclusions are indicators of the method.