Lab-Grown Diamonds: The Origin Story

While technological advances in producing lab-grown diamonds continue to improve, technological advances in producing natural diamonds have not. In “Lab-Grown Diamonds,” Javid Lakha provides an overview of the history of lab-grown diamonds and their implications for everything from jewelry to industrial cutting equipment. (Work in progress(No. 16, August 30, 2024) Here, Laka tells the story of the origin of lab-grown diamonds.

In 1950, General Electric Laboratories in Schenectady, New York, organized a consortium of chemists, physicists, and engineers to form Project Superpressure, a project to synthesize diamonds in the laboratory. … To support the research, General Electric commissioned a $125,000, two-story, 1,000-ton hydraulic press. Four years of intensive experimentation followed, during which Project Superpressure exhausted its original research budget and two additional rounds of funding. When the project managers requested more funding a third time, General Electric’s research managers, having seen no tangible results and skeptical of future success, voted almost unanimously to end the funding. Guy Suits, General Electric’s research director, overruled them and approved the funding. …

On December 16, 1954, Howard Tracy Hall, a chemist and member of the Project Superpressure team, placed two diamond seed crystals in a graphite tube containing iron sulfide and covered them with tantalum disks. The graphite in the tube served as a carbon source, and when an electric current was applied to the tantalum disks, they acted as resistance heaters. He then placed this cylindrical device in a pressure chamber of his own design. Hall’s pressure chamber, now known as a belt press, consisted of two opposing tapered anvils that compressed the reaction cell from above and below, with the sides supported by prestressed steel bands.

Hall explains that when he conceived the device, his colleagues “felt negative about it.” His offer to build a prototype that would have cost less than $1,000 was rejected by General Electric, and he was also refused time to spend in the machine shop building it. “I was worried about this for a while,” He wrote‘Then we decided on the sub-rosa solution. Friends at the machine shop unofficially agreed to make the Belt in their spare time. This took months. Normally it would have taken only a week.’

A practicing Mormon who had little time for fellow workers because of his church and large family, Hall attributed the refusal to build his designs and other insults to religious prejudice. When his circular belt device proved capable of reaching high pressures and temperatures, Hall asked that its critical components be rebuilt from carboloy (cobalt-cemented tungsten carbide). Once again, his request was denied, and until his former boss intervened, he was unable to obtain permission to purchase carbide components.

Compounding Hall’s sense of injustice was the fact that demand for Project Superpressure’s thousand-ton press was so high that Hall’s improved pressure chamber was “relegated” to (in his words) an “ancient” press from the early 20th century. It could only press 400 tons and was still hydraulically operated. Hall later described the press as “leaking so badly that rubber shoes, mops and buckets were standard equipment.”

Using this ancient press, Hall compressed the pressure chamber to 10 gigapascals (about 100,000 times atmospheric pressure) and heated the reaction chamber to 1,600°C. The experiment lasted 38 minutes. Hallmade a diamond:

I broke the sample cell I had taken from the belt. It cracked near the tantalum disc used to supply current for resistive heating. My hands began to shake. My heart raced and my knees grew weak, unable to support me anymore. My eyes caught the flash of light from the dozens of tiny triangular facets of the octahedral crystals attached to the tantalum, and I finally knew that diamonds were man-made.

General Electric repeated Hall’s results 20 times over the next two weeks, and on February 15, 1955, announced to the world that it had created the first diamond in its laboratory. The press release suggested that the diamond had been created in a new, 1,000-ton press. Hall’s compensation was slightly increased from $10,000 to $11,000 a year, plus $10 in savings bonds. He resigned from General Electric and became a full professor at Brigham Young University. …

Meanwhile, Hall was forbidden by a secret order from the U.S. Department of Commerce to disclose details of his belt press or to use it to conduct further research into high-pressure chemistry. During World War II, diamond supplies were a source of anxiety for both the Allies and the Axis. With no domestic supply of diamonds, the United States relied on the De Beers cartel for diamonds needed for industrial production, and De Beers’ business model was to artificially restrict world supply to drive up prices.

Lab-grown diamonds: The story of their origins first appeared in Conversable Economist.