Diamond Irradiation Treatment

Types of Irradiation Treatments To Alter A Diamond’s Color

If you are an avid collector of diamonds, you’ve probably already heard of irradiation treatments. Irradiation is a method used to alter the color of colorless or off-color diamonds. This method involves the exposure of the diamond to electromagnetic rays in order to release its electrons, thereby resulting in the re-arrangement of their crystal lattice.

The process of irradiation is nothing new. Way back in 1904, Sir William Crookes discovered that diamonds immersed in radium salt turned green. These diamonds were not safe to wear as jewelry however because of the radioactivity of the stones from the process involved. However, Sir William Crookes’ technique was fine tuned and perfected over time because his basic idea was promising. The idea that one could transform a naturally colorless diamond into a green, black or blue diamond was indeed exciting.

Irradiation is used mostly for natural diamonds. There are a lot of irradiated diamonds that have made their mark in the world, such as the Dresden Green Diamond and the Deepdene, which is the largest known irradiated diamond. There are different types of irradiation methods. Among the most popular are: (1) electron bombardment; (2) neutron bombardment; and (3) gamma ray exposure. Other methods also use alpha particles and beta particles, depending on the type of diamond or stone that is being treated.

Electron Bombardment

In order to change a diamond into one with a greenish color, an electron accelerator or linear accelerators is used to expose the stone to high-energy electrons. After such exposure to the electrons, if another change in color is desired, the diamonds are then subjected to the process of annealing in order to turn the stones into yellow, orange or brown diamonds.

Neutron Bombardment

Gemologists have termed the irradiation of diamonds using an electronic beam nuclear reactor and controlled heating as annealing. An originally colorless or even colored diamond’s appearance is improved or altered as a result of its exposure to high-energy neutrons.

By using the electro-beam nuclear reactor, the diamond is transformed to look exactly like a natural fancy colored diamond. Experts and diamond connoisseurs will not be able to detect if your diamond was treated using the annealing process. They would need a very sophisticated and high-tech piece of equipment to determine the original color of your diamond.

Gamma Ray Exposure

Gamma ray exposure or bombardment of diamonds involves exposing the diamonds to cobalt-60. It is said that gamma ray exposure is the most safe and most cost-effective way to treat diamonds. Here, the diamond is exposed to cobalt-60 over a period of several months. A blue to blue-green diamond results after the entire process. There is no need to anneal the diamonds after.
The original color of the diamonds that are subjected to gamma ray exposure is usually on the yellow end of the spectrum. The blue from the cobalt-60 modifies its appearance, thereby producing a blue to blue-green stone.
In order for experts to detect whether irradiation has been done to a diamond, they use a spectrophotometer, which detects the effects of radiation, as these effects are permanent.