Gemologists have always been fascinated by the prospect of creating a beautiful and precious diamond from basic carbon. Many have attempted to perform this incredible feat, much like the alchemists of the past who attempted to transform lead into gold. But we have been able to generate gem-quality lab-grown diamonds that are large enough to be used in jewelry only recently. However, their authenticity is not doubted. Stephen Morisseau, a spokesman for the Gemological Institute of America—a nonprofit organization overseeing the international diamond grading system, opines:
[Lab-created diamonds] are not fakes. They are not cubic zirconias. They have the same physical and chemical properties as a mined diamond.
Be that as it may, the question that should be asked is, ‘how does one go about doing it?’
Many individuals have claimed to have successfully manufactured diamonds throughout history. It was not until recently, however, that a documented and repeatable procedure was proven. One of the first pioneers in the discipline was Henri Moissan. He claimed in 1893 that he had created a diamond by heating charcoal to 3,500 degrees Celsius within a carbon crucible. Many attempts to replicate his techniques were attempted, with some success reported, but none of them could ever be scientifically validated. The search went on.
Diamonds are crystalline forms of carbon, which is why creating artificial carbon crystals was a challenge for lab-grown diamonds. Manufacturers of synthetic gemstones attempted to grow diamonds in the same way as rubies, sapphires, and emeralds have been grown for decades, but the process was a flop. Afterward, they introduced the concept of growing diamonds in the lab in the same way that they develop in nature.
High-Pressure High-Temperature Diamonds
Natural diamonds form deep underground, approximately 100 miles beneath the earth’s surface, due to extremely high pressure and temperatures. When a unique form of a deep volcano sends diamonds closer to the planet’s surface, people can discover and mine them.
Most people are still ignorant of how diamonds are made in a lab. High-Pressure High Temperature (HPHT) and Chemical Vapor Deposition (CVD) are the two most popular techniques for creating lab diamonds (Chemical Vapor Deposition). However, CVD is favored in producing high-quality diamonds.
High Pressure/High Temperature (HPHT) manufacturing was used to create the first effective synthetic diamonds. HPHT diamonds are made using three primary production processes: the belt press, the cubic press, and the split-sphere (BARS) press. The objective of each procedure is to produce a high-pressure, high-temperature environment conducive to diamond formation. Each procedure begins with a tiny diamond seed embedded in carbon and subjected to extreme pressure and heat to develop the diamond.
The GE belt press generates pressures of over 1.5 million pounds per square inch and temperatures of over 2,000 degrees Celsius using an upper and lower anvil. The pure carbon melts in this atmosphere and begins to build a diamond around the starting seed. The first repeatable lab-produced diamond was created on December 16, 1954, using a belt press. Although the diamond was small and not clear enough to be used in jewelry, it was still a start. It is important to note that the majority of artificial diamonds created today are not of gem grade. Instead, they are designed for industrial applications where diamonds’ incredible characteristics, such as hardness and thermal conductivity, are employed to improve tools and equipment.
HPHT diamond development takes place in a tiny capsule inside a machine capable of producing extremely high pressures. A carbon starting material, such as graphite, dissolves in a molten flux of metals like iron (Fe), nickel (Ni), or cobalt (Co) within the capsule, lowering the temperature and pressure required for diamond formation. The carbon material then migrates through the flux and crystallizes on the colder diamond seed, forming a synthetic diamond crystal. Crystallization happens over days to weeks, resulting in the formation of one or more crystals.
HPHT technology has progressed steadily since its initial breakthrough with the belt press. Belt press designs have been substantially scaled up, and more efficient cubic and split-sphere presses have been created, resulting in larger, more flawless diamonds. NDT is credited to have produced the world’s biggest gem quality, faceted, lab grown diamond utilizing the HPHT technique and a cubic press. This magnificent diamond is rated E color and VS1 clarity and weighs 10.02 carats.
Features of CVD and HPHT Diamonds
Both of the primary diamond-making methods produce final diamonds with distinct characteristics. Silicon inclusions are sometimes seen in CVD diamonds. These are caused by the ionized gases etching off silica windows in the development chamber and introducing them into the diamond as it develops. True colorless stones are tough to make using HPHT diamonds, given that the tiniest amount of nitrogen or boron present throughout the procedure might produce a yellow or blue hue. When compared to natural diamonds, both HPHT and CVD diamonds have significant and unique fluorescence properties. While this does not affect the look of the diamonds in general, it is quite helpful in recognizing them as lab produced.
Which diamond to buy
If you are thinking about getting a lab-grown diamond, you could be debating between an HPHT diamond and a CVD diamond. Both technologies are intriguing, each having their own set of advantages and disadvantages. Thankfully, you do not have to be concerned about how your lab-grown diamond was created. The beauty of a lab produced diamond, like that of real diamonds, stems from its physical qualities rather than the specific process by which it was created. Besides, it is proven that lab grown diamonds are more ethically produced than naturally mined ones—another reason you should prefer diamonds made in a lab than those that develop inside the earth. The 4Cs are used to grade and price lab produced diamonds, as is the case with natural diamonds. Each form of lab produced diamond may have somewhat varied inclusions and color variations, but the ultimate product is an essential factor. A CVD diamond with G color and VS2 or VS1 clarity will sparkle equally as brightly as a G color, VS1/VS2 HPHT diamond (assuming they were cut to the exact proportions).