Lab Grown Diamonds Fundamentals Mini Course
A Brief History of Lab-Grown Diamonds
at James Allen
What are Lab-Grown Diamonds?
As the name indicates, lab-grown diamonds (also known as synthetic diamonds) are created or "synthesized" in laboratories. To understand this process, you must first understand how natural diamonds form.
Natural diamonds form up to 150 miles below the Earth's crust, where carbon is compressed under extremely high temperatures and pressures. Scientists produce synthetic diamonds under the same conditions but in laboratories, using a variety of methods to compress carbon at high temperatures and pressures to make it crystalize.
The First Lab-Grown Diamonds
People have been trying to create diamonds since their true nature as pure carbon was discovered by Antoine Lavoisier in 1772. (Shigley, 2024) One of the more interesting methods, albeit highly impractical and dangerous, was outlined by H.G. Wells in his 1894 short story The Diamond Maker. His method involved high temperatures and pressure, an approach that, with some modifications, would become the foundation for successful diamond synthesis 60 years later.
Throughout the 19th century, many attempted to recreate in a lab setting the conditions necessary for diamond formation. Although there were many claims of success, scientists couldn't replicate these experiments.
Project Superpressure
The first proven synthetic diamonds were made by GE in 1954, under a project codenamed "Project Superpressure." This project began in the 1940s, but World War II postponed the work. For years, scientists experimented with various methods, temperatures, and pressures to produce diamonds from carbon. Using a high-pressure belt press, they subjected small seed crystals to temperatures of 1,600º C (2,912º F) and pressure of 100,000 atm. In this device, they dissolved graphite — another mineral made of pure carbon — in metals, including iron, nickel, and cobalt, to accelerate the transformation of graphite to diamond.
When the resulting material broke the scientists' cutting tools, they believed they had succeeded. With a Mohs hardness of 10, diamonds can famously scratch and destroy metal tools. They subsequently confirmed that they had, indeed, made diamonds. A team of scientists, including both Herbert Strong and Howard Tracy Hall, received credit for this discovery.
The ASEA
Around the same time as Project Superpressure, the Swedish company ASEA (Allmänna Svenska Elektriska Aktiebolaget) also achieved success. In February of 1953, they became the first to grow 40 small diamond crystals, though they delayed announcing their achievement. (Liander, 1955)
The First Gem-Quality Lab-Made Diamonds
The 1950s may have marked the start of the lab-grown diamond industry, but early on, there was little concern about them competing with natural diamonds. The diamonds GE produced via their process were far too small for gem use. Instead, they were used for industrial purposes.
The First Lab-Grown Diamonds Analyzed by the GIA
Nevertheless, this discovery paved the way for GE to create gem-quality crystals in 1971. Their process used a tube to add heat and pressure to a graphite seed in the center until it grew into diamond. The first stones sent to the Gemological Institute of America (GIA) for analysis were between 0.26 and 0.30 carats, in colors ranging from F to J. (GIA, 2013)
The Limitations of Early Gem-Quality Lab-Created Diamonds
Although an incredible discovery, using such high-temperatures and pressures to produce these stones was too expensive to compete economically with natural diamonds. Furthermore, these first gem-quality synthetic diamonds were often yellow and also contained many inclusions. Such stones wouldn't receive high grades according to the color and clarity standards for white or colorless diamonds.
Improvements to Early Lab-Created Diamonds
Research revealed an excess of nitrogen in the gems caused the yellow color. Some further adjustments lead to the production of colorless diamonds. Within a few decades, research by scientists in the United States, Russia, and China made it possible to create diamonds in laboratories that could exceed natural diamonds in carat (size), color, and clarity. Slowly, these gems made their way into the diamond market.
at James Allen
Modern Methods
The method initially developed by GE is a high pressure/high temperature process (HPHT). This method mimics diamond-forming conditions underground. However, reproducing such conditions is expensive and complex. (In 1999, GE developed an HPHT treatment to improve the color of white diamonds).
Today, most lab-grown diamonds are made through a process called chemical vapor deposition (CVD). In this method, carbon gas heats a diamond seed in a chamber, causing the carbon to stick to the seed and grow into a larger diamond. CVD gives scientists more control over the properties of lab-grown diamonds and makes possible the production of large, gem-quality diamonds. CVD can also take place at lower pressure and temperature, which makes the process much less costly.
The first patent for CVD was issued in the 1950s. However, scientists didn't refine the process so it could produce gem-quality diamonds until the 1980s. It took even longer to make this process commercially viable, since only one seed could undergo CVD at a time. This was quite costly - likely tens of thousands of dollars per stone.
However, the cost of the technology has come down. It's been reported by industry analysts that the cost to produce a lab grown diamond in 2008 was $4,000 per stone. Now, it's $200-$300 per stone and falling every year as dozens of seed diamonds can undergo CVD at once. (The exact number is unknown and regarded as a trade secret).
at James Allen
The Increase of Lab-Grown Diamond Production
According to Bain & Co. (as reported in Linde et al., 2021, and later in Eaton-Magana et al., 2024), lab-grown diamond production was estimated to be between 6 and 7 million carats in 2020, primarily from China, India, and the U.S. An earlier report from 2018, by industry analyst Zimnisky, estimated that lab-grown diamonds accounted for 3.4% of jewelry sector sales worldwide. (Eaton-Magana et al., 2024) He projected that this figure would rise to 7.5% by 2021. This forecast that was later confirmed by D'Haenens-Johansson et al. (2022), who reported the market share to be between 5% and 8%.
A major turning point came in 2007 when the GIA officially recognized lab-grown diamonds by beginning to issue reports on them. Prior to this, lab-grown stones may have been submitted for analysis but were not officially graded or documented. In this first year, lab-grown diamonds accounted for just 0.05% of all diamond reports issued. While this may seem like a small figure, it is significant considering the vast number of diamonds sold annually.
In July 2019, following guidance from the Federal Trade Commission (FTC), the GIA updated its terminology on these reports to read "lab-grown" to avoid consumer confusion.
Changing the Diamond Industry
The demand for lab grown diamonds substantially increases every year. Synthetic diamonds cost 30-40% less than natural diamonds, and growing consumer interest in ethical diamond sourcing makes these stones an appealing option to mined diamonds.
Lab-grown diamonds combine stunning looks and lower prices with ethical sourcing. This is making an impact on the diamond industry. Even De Beers, the world's largest diamond mining company, has started a lab-grown diamond line called Lightbox to meet this rising demand.
Younger buyers find synthetic diamonds especially appealing, and not just because of lower prices. These consumers have a greater awareness of the ethical and environmental problems that diamond mining can pose.
at James Allen
References for a History of Lab-Grown Diamonds
GIA, 2013, "Synthetic Diamonds: From Dark Industrials To Bright Gems."
D'Haenens-Johansson, U.F.S, Butler, J.E., Katrusha, A.N, 2022, "Synthesis of Diamonds and Their Identification," Reviews in Mineralogy & Geochemistry, Vol 88.
Eaton-Magana S, Hardman M.F, and Odake, S, 2024, "Laboratory-Grown Diamonds: An Update on Identification and Products Evaluated at GIA," Gems & Gemology, Vol 60 No.2.
Liander, H, 1955, "Artificial Diamonds," ASEA Journal.
Linde, O., Epstein A., Kravchenko, S., Rentmeesters, K., 2021, "Brilliant Under Pressure: The Global Diamond Industry 2020-21," Bain & Co.
Shigley, J.E., 2024, "Historical Reading List: Historical Attempts to Synthesize Diamonds," GIA.
Amanda Butcher
Amanda is a student of geological sciences and environmental studies at Tufts University. She grew up hiking and mountain biking in the Bay Area and continues to explore nature and learn about the beautiful gems and minerals it forms in her free time.
Andrew Fellows
Andrew Fellows has served as a diamond and gemmology lecturer at Birmingham City University for the BSc in Gemmology and Jewellery Studies course, as well as a course leader for the MSc Gemmology course based in the Gemmology Department at the Assay Office. Prior to teaching at Birmingham City University, Andrew was responsible for course creation and maintenance at Gem-A. Andrew started his career as a diamond grader at J.E. Marlow & Sons and in jewellery production at G&A Manufacturing.
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