It’s not a secret that diamonds found on the earth are not totally perfect. Commonly, they have yellowish and brownish tints or visible internal flaws that make the stones look unclean. However, there are different treatment methods that can solve these problems. Let’s see what exactly diamond treatments are and how they can improve colour and clarity.
Colour-Enhancing Diamond Treatments
High-Pressure, High-Temperature Treatment (HPHT)
As the name refers, HPHT is a technique to turn yellowish and brownish diamonds into colourless stones by heating them under high pressure.
This type of colour enhancement is permanent, meaning the colour of the stone does not revert to its original state.
HPHT treatment can be hard to detect which is why the Federal Trade Commission (FTC) requires it to be explicitly disclosed.
Grading reports issued by the Gemological Institute of America (GIA) always contain a note about HPHT treatment if detected. In some cases, treated diamonds may also have a laser inscription indicating the treatment.
It’s important to understand that not all grading labs include inscription and mention of the treatment in their certificates. That’s why it’s useful to ask the seller about the labs they use for grading.
The coating is another method to make diamonds look whiter. Diamonds get covered with a dye or thin film that masks the tint and make them look colourless.
The coating is not permanent. It can be easily removed with water or alcohol.
This treatment method is also used to make fake stones look like real diamonds. In other words, if such a treatment is not disclosed it’s a scam.
This colour enhancement method is used to turn diamonds into fancy-coloured stones.
Naturally coloured diamonds are very rare and very expensive as a result. Here comes irradiation, which is used to produce affordable coloured diamonds.
The result of irradiation is permanent, however, in some cases, the colour of the diamond may change if the stone was subjected to high temperature during jewellery repairs. That’s why always make sure the jeweller is aware of the treatment.
The downside of irradiation is that there are vendors who try to sell treated fancy-coloured diamonds as natural ones at a very high price. And the opposite, they sell it at a lower price but claim it’s a “natural” fancy-coloured stone. To avoid such suspicious offers, always ask for a certificate issued by a reputable laboratory.
Clarity-Enhancing Diamond Treatments
Laser drilling is a method used to improve the clarity of a diamond.
During this process, a thin channel is drilled with a laser from the surface to the inclusion of the diamond, which is then burned out.
Laser drilling is a permanent treatment, which is why FTC doesn’t require explicit disclosure.
If the diamond is certified by GIA, the grading report will list the drill holes in the stone. These holes will also be visible under a microscope.
It’s always good to know if the clarity of the stone has been improved by this method, as too many drills may weaken the structure of the stone.
After laser drilling, the channels and the hollows can be filled with a transparent crystalline substance. This masks the remaining cavities and makes them look less visible.
Fracture filling is not permanent. Heating and putting such a diamond in an ultrasonic cleaner may destroy the filling. That’s why such treatment should necessarily be disclosed.