Treatment Processes For Diamonds

Diamond treatments have been around for quite a long time. The term treated automatically makes a diamond sound less valuable. I believe that treatments have a place in the diamond industry providing a lower cost for customers without forcing the customer to sacrifice either weight or cut quality.

diamond treatments

Laser Drilling

The first method of diamond treatment I will discuss is laser drilling. The reason a diamond would be laser drilled is to improve the clarity grade. The diamonds selected for this type of treatment usually have large dark, eye visible inclusions.

The diamond is then drilled into with a laser to the inclusions and the “color” of the inclusion is burned out. Burning out the inclusion involves submersing the diamond in an acid and pressurizing the container, forcing the acid through the laser drill hole and into the inclusion, thereby making the inclusion appear white or colorless and less visible.


  • The treatment is permanent and stable.
  • An eye visible inclusion is usually made visible only under magnification.
  • GIA will issue certificates on diamond with this type of treatment.


  • The laser drill hole remains and can be seen under magnification.
  • The diamond is now considered treated and is less saleable.


Irradiation is a method of treatment to change the color of a diamond. Diamonds that are selected for irradiation usually have a dark yellow or dark brown body color. This type of diamond is much less saleable than a colorless or a fancy color diamond so the diamond is placed in a cyclonic chamber and is bombarded with radiation (similar process to sterilizing medical equipment) until the color is improved.


  • The color is usually permanent and stable.
  • The diamond is much more saleable in the new color.
  • The cost of an irradiated diamond is much lower than an untreated diamond of the same color.


  • The color of an irradiated diamond is not exactly the same as an untreated fancy color diamond.
  • Sometimes irradiated diamonds can be color zoned which is visible to the eye.
  • Rarely diamonds that are irradiated are radioactive and are confiscated by the US government.

The bottomline is, when a diamond has been treated, it has to be properly disclosed to the consumer.