Treated Diamonds

Treated diamonds are natural diamonds that have been subjected to one or more treatments or enhancements to change the physical appearance of the diamond. Some of these treatments are permanent and some are temporary.

The type of treatments that exist at the moment are:

Colour treatments:

  • Coating is the application of a foreign substance on a diamond to alter its colour. This treatment is temporary.
  • Irradiation is the process by which a diamond is exposed to radiation to modify the colour of the diamond to green, blue or black. This treatment can be combined with high temperature as well to change the diamond in other colours such as yellow red or pink. This colour change is permanent.
  • HPHT treatment is used to turn brown diamonds in colourless or fancy colour diamonds. Some type IIa diamonds are not completely grown and HPHT treatment is giving those stones an apportunity to complete their growth process and becoming the colour nature had intented forthem. Type IIa diamonds can turn in pink or colourless diamonds and type IIb stones can turn blue. This treatment can also be applied on type I diamonds. In that case they usually turn into a very vivid yellow or orange colour.
  • High temperature (HT) is a colour modifying treatment to create black diamonds from industrial boart.

Clarity enhancements

  • Laser drilling combined with deep boiling is the creation of a long tube in the diamond to reach one or multiple big black carbon inclusions in the diamond. Once that inclusion has been reached by the laser drill the stone is put in acid to dissolve the impurities. This treatment is usually only done with low quality diamonds to improve their visual appearance. When you laser drill a diamond you create a new inclusion in the stone as such this enhancement never improves the real defects of the stone. This treatment is permanent.
  • Fracture filling is the application of a silicone liquid to open fractures near the surface. When diamonds have large natural cracks, it blocks the passing of light trough the diamond, fracture filling resolves this issue by injecting a substance of similar light refraction in the diamond so the light can move freely through the stone. Fracture filling is a treatment that can be easily observed when looking at the diamond at 10X magnification, when moving the stone in the right angle suddenly a rainbow effect will be visible.