Glossary

As Grown -

Lab-Grown Diamonds that are grown as is, without any post-growth treatment to enhance their color or appearance.

HPHT -

The High Pressure Heat Treatment (HPHT) method is the oldest form of growing diamonds in a laboratory setting. Using HPHT, a diamond seed is exposed to temperatures of over 2,000 degrees fahrenheit and pressure of about 1.5 million PSI (pounds per square inch). Carbon melts and adheres to the seed, forming a complete rough diamond as it cools. HPHT may also be used, as a post-growth treatment of CVD grown diamonds, to enhance their color or appearance.

CVD -

Chemical Vapor Deposition (CVD) was first explored for the growing of diamonds in the 1980s. Recently CVD been used to grow high-quality diamond material for gem and other applications. In the CVD method a seed is placed in a chamber, where carbon-containing gases are activated, using a plasma discharge, allowing the carbon to settle on a seed and grow a complete rough diamond. CVD is a much less costly process than HPHT because it works at moderate temperatures and low pressure, which requires smaller and less expensive equipment.

Post Growth Treatment -

When a diamond is grown in laboratory it does not always achieve the color level the grower desired for commercials sales. When this occurs post-growth treatment of the diamond can be used to improve the color and appearance of the diamond. HPHT is most commonly used, as a post-growth treatment of CVD grown diamonds, to enhance their color or appearance. This treatment has also been used with mined diamonds.

Seed -

A small piece of a single crystal diamond (either mined or lab-grown) that can be used to start the growth of a new diamond in a lab, with either CVD or HPHT processes.

Chamber -

Sometimes called a reactor, a chamber is a vacuum sealed container within which a diamond is grown using the CVD method.