Patent Applications for HPHT

Both General Electric and De Beers have filed for world patents on the high-pressure, high-temperature diamond-treatment process. GE’s two patents include one for creating fancy yellowish-green, greenish-yellow, and neon yellow-green diamonds from brownish type Ia diamonds (#WO 0114050 High Pressure/High Temperature Production of Colored Diamonds). These are the types of colors formerly produced by NovaDiamond in Provo, Utah, before it left the gem diamond market. A second patent filing is for the identification process of HPHT diamonds (#WO 0133203 Method of Detection of Natural Diamonds That Have Been Processed at High Pressure and High Temperatures).

Michelle Kalina, marketing director for GE’s Gem Technologies division, says the jewelry industry shouldn’t be concerned about patents filed by General Electric. “GE, as a technological leader in many industries, has thousands of patents,” writes Kalina. “GE uses patents to protect the company’s hard-earned intellectual property and ensure that GE will benefit from its own inventions. It’s not GE’s intention, however, to use any patent position it may achieve to prevent HPHT processing detection from gaining widespread acceptance in the gem grading laboratories within the diamond industry at large. It is GE’s position, however, to do all it can to ensure that all entrants into the HPHT field follow the ethical path of full disclosure. Our sole goal is, and always will be, to uphold the integrity of our product.”

De Beers also has filed for HPHT patents: one on the creation of colorless diamonds from type IIa brown diamonds, a second on creating blue diamonds from type IIb gray diamonds, and a third for changing the color of a brown type IIa diamond to pink (patents #WO 0172404, #WO 0172405, and #WO 0172406, all titled High Temperature/High Pressure Colour Change of Diamond).

All five patent applications can be found on the Web at