Did you know many gemstones bought from high-street jewellers today have been treated? If you would like to know more about diamond and gemstone heat treatment read our guide to discover what heat treatment involves and how it affects a gemstone's value.
What Is Heat Treatment?
One of the most common forms of gemstone treatments you will hear about is 'heat treatment' which involves subjecting a gemstone to high temperatures to alter or enhance its colour.
Gemstones that are often heat treated include: amethyst, aquamarine, citrine, ruby, sapphire, tanzanite, topaz, and tourmaline.
Colours are altered to become more vivid, brighter, and in a lot of cases more attractive. Tanzanite for example is often heat treated to bring out its exquisite violet purple shade. When tanzanite is first mined it often appears dull brown which is not as attractive as the tanzanite we see adorned on jewellery.
White Gold Tanzanite and Diamond Ring
Is a Heat Treated Gemstone Less Valuable?
The important thing to remember is that a heat treated gemstone is still a real gemstone. In fact, heat treatment is such a common practice among gemstones that there is very little effect on value.
However an exception to this rule is the fancy colour diamond. 1 in every 10, 000 diamonds mined display a naturally occurring 'fancy' colour such as blue, brown, yellow, pink, green, black or even red - the latter being the rarest of them all. If a traditional clear diamond has been heat treated to artificially create a 'fancy' colour then this diamond will be less valuable than a genuine naturally occurring fancy colour diamond.
All diamond and gemstone retailers should clearly label in the product description if a fancy diamond is real or has been artificially coloured or heat treated.
Where Can I Buy Fancy Colour Diamonds?
If you are interested in purchasing jewellery crafted with genuine fancy colour diamonds, head over to our second hand collection on our T H Baker online store. Established in 1888, we have 130 years expertise as a jewellery retailer.
Second Hand Platinum White and Champagne Diamond Twist Ring - available at T H Baker
We hope this guide to diamond and gemstone heat treatment has cleared up any queries you have.
For more in depth information about diamond and gemstone treatments we recommend you read the guide by GIA (Gemmological Institute of America).