HPHT Process

Diamonds with a slight colouring go through the HPHT process to make them appear whiter. Slightly tinted diamonds may also be colour-enhanced to enrich their colour, giving them a distinct tone, like yellow or pink, whatever may be desired.

The HPHT method exposes stones to extremely high temperatures and very high pressures. In fact, the conditions are similar to those in which the stones were formed millions of years ago. The treatment is irreversible, as it essentially upgrades the diamond’s color. Depending on the original stone, the change in color can be slight, or quite dramatic.

Certain diamonds can be processed to create white or near white diamonds using the HPHT treatment.

Diamonds with a slight coloring go through the HPHT process to make them appear whiter. Slightly tinted diamonds may also be color-enhanced to enrich their color, giving them a distinct tone, like yellow or pink, whatever may be desired.

On client’s approval, the diamond is submitted to our lab for HPHT processing. This process usually takes 10 to 15 business days. The stone is returned to the client as soon as it is ready.

The CVD Method

The CVD method was created in the 1980s, making it newer than the HPHT method. The CVD method imitates how diamonds form in interstellar gas clouds. The CVD method uses less pressure than the HPHT method as well as smaller machines.
The CVD method places a diamond seed in a vacuum chamber. This chamber becomes filled with carbon-rich gases and is heated to nearly 1500 degrees Fahrenheit. The gas turns into plasma from these extremely high temperatures, causing the release of carbon pieces. These carbon pieces become layered onto the diamond seed, which grows the diamond.

The CVD process produces Type IIA diamonds, which are extremely rare for naturally occurring diamonds. This can help scientists determine if a diamond is lab-grown or earth-grown. Type IIA diamonds are the most chemically pure diamonds. CVD diamonds are not magnetic like HPHT diamonds can be.