Synthetic diamonds go by many different names—lab-grown diamonds, lab-created diamonds, lab-grown diamonds, and even man-made diamonds. These names all refer to the fact that synthetic diamonds are created in a laboratory or factory, rather than being formed naturally in nature and mined from the earth. Some synthetic diamond laboratories use advanced technology to simulate the conditions under the Earth’s crust where natural diamonds form. This formation process is the main factor that distinguishes synthetic diamonds from natural diamonds, after all, synthetic diamonds essentially have all the same chemical, optical, physical properties and crystal structure as natural diamonds.
Synthetic Diamond Timeline
1950s: Synthetic diamonds are introduced, produced using the high-pressure, high-temperature (HPHT) method, and are used primarily for industrial purposes, such as in telecommunications and laser optics, and as abrasive materials.
1970s: General Electric researchers create the first gem-quality synthetic diamonds. They are clear enough and large enough to be used as gemstones in jewelry.
Mid-1980s: Manufacturers begin producing gem-quality synthetic diamond crystals on a commercial scale. At first, these lab-grown diamonds were mostly small and yellow or brown, but their quality improved over the next few decades.
2000s: Diamonds are grown using chemical vapor deposition (CVD), which requires lower pressures and temperatures than the HPHT method.
Mid-2010s: Colorless laboratory-grown diamonds become available on a commercial scale for the jewelry market. HPHT and CVD remain the primary production methods for synthetic diamonds.
CVD synthetic diamond (left), HPHT synthetic diamond (center), and natural diamond crystal (right). The CVD diamond is coated around the edge with carbon that accumulates during the manufacturing process.
How are synthetic diamonds created in a laboratory?
There are two main processes used to create diamonds in the laboratory:
1. High Pressure, High Temperature (HPHT)
Synthetic diamonds are created using this method, where the laboratory simulates the high pressure and temperature conditions under which natural diamonds are formed in the earth. HPHT diamonds are created at pressures of 5–6 GPa (about the pressure of a commercial jet resting on a human fingertip) and temperatures of 1300–1600°C.
Lower quality natural and synthetic diamonds can be treated with HPHT to improve their color and clarity. In addition to improving the color grade of colorless diamonds, this process can also be used to change the color of diamonds to pink, blue or yellow. These diamonds are called “treated” diamonds.
2. Chemical Vapor Deposition (CVD)
Using this relatively new technology, scientists are able to create synthetic diamonds at moderate temperatures (700°C to 1300°C) and low pressures. Carbon-containing gases are pumped into a vacuum chamber, deposited on a diamond seed crystal, and crystallized into a synthetic diamond. The final size of the diamond depends on the time allowed to grow.
How to Identify a Laboratory-Grown Diamond?
To the naked eye, synthetic diamonds (left) and natural diamonds (right) look the same.
Natural diamonds are formed deep in the Earth’s mantle over millions or even hundreds of millions of years, and are brought to the Earth’s surface when kimberlite and lamprophyre volcanoes erupt. Many natural diamonds also contain strange inclusions. Laboratory-grown diamonds look exactly like natural diamonds and are difficult to distinguish with the naked eye. They generally need to be tested and identified in a laboratory equipped with advanced instruments.
How are laboratory-grown diamonds graded?
GIA Natural Diamond Grading Report.
At GIA, synthetic diamonds go through the same rigorous grading process as natural diamonds . When GIA receives a gemstone for grading, it tests it to confirm its identity and detect possible treatments. Analysis methods include looking for inclusions as well as fluorescence and phosphorescence. If a diamond is found to be synthetic, GIA issues a Laboratory-Grown Diamond Report . As an additional precaution to protect consumers, GIA also laser inscribes the diamond’s girdle with its report number and a statement indicating that the diamond is laboratory-grown.
Laboratory-grown diamonds have become a mainstream alternative for many people today, as they offer the same beauty and properties as mined diamonds, and are often much less expensive. Whether you are considering buying a laboratory-grown diamond or a natural diamond, you can know its identity and quality by purchasing a gemstone with a GIA Diamond Report .
