For over a hundred years all of the attempts at making synthetic diamonds centered on discovering a process later nicknamed HPHT for high pressure, high temperature. Various devices have been built to achieve the high pressure and high temperature needed to transform carbon into diamond, but the industry finally settled on a method called BARS as the most efficient, compact and therefore economical process. The next process that has been researched extensively for its simplicity is known as chemical vapor deposition or CVD, and which allows for the growth of a kind of diamond coating on materials. Two other processes that have been discovered but not put to any wide scale industrial use yet because of various inefficiencies include the detonation of carbon containing explosives in a metal chamber and ultrasound cavitations, which holds promise but has not yet been optimized

With the variety of different processes used to create synthetic diamonds an array of differences in their physical properties are achievable for the skilled technician. Varying levels of hardness, size of a single crystal, and presence of impurities or inclusions all affect the end purpose synthetic diamonds will be used for. The first synthetic gem quality diamonds were produced in 1971 and further advances have made it possible to create even more perfect specimens for jewelry. The first gem quality stones were made up of a large continuous crystal instead of several smaller crystals growing closely together, but often had a yellow hue from contamination with nitrogen. Many of the synthetic diamonds produced have ended up revolutionizing various industries. Smaller non-continuous crystals, for instance, have made their way into industry as abrasives in cutting and polishing tools. Very strong but not clear larger diamonds can be fashioned into cutting tools, for diamond is the strongest substance known to man. While a pure diamond is excellent at conducting heat but a poor conductor of electricity, they can be used to create a heat sink, which slowly dissipates thermal energy without changing the flow of an electrical current. With the purposeful inclusion of impurities such as boron or phosphorus, synthetic diamonds are changed into a semiconductor of electricity, which has made possible new electronics technologies such as LED. Although probably not exactly the intentions of those first alchemists, the synthetic diamonds produced today have revolutionized many different industries and we are only beginning to imagine the practical applications of these beauties.