Synthetics, also known as laboratory-grown gemstones, are identical to natural gemstones, in their chemical, physical and optical properties, but they are grown and manufactured in laboratories in different methods, meaning they are man-made and not earth mined. The most common synthetic gemstones include diamonds, emeralds, sapphires, rubies, quartz, spinel, alexandrite, and opal. Synthetic gemstones vary in price and in quality. By the law, it is required to fully disclose to the consumer if the gemstones are synthetic. We at Riginov offer our customers only natural gemstones and do not recommend purchasing any synthetic gemstones. Please note that synthetics gemstones, are not to be compared with simulants or treated gemstones.
Synthetics Diamonds are the result of a technological process, as opposed to the geological process that creates natural diamonds. Two common production methods are used to manufacture diamonds in a laboratory: HPHT and CVD. Laboratory-grown diamonds are becoming more widespread and increasingly difficult to detect. Since HPHT and CVD diamonds are virtually identical to natural diamonds, differences only become clear when they are analyzed in a gem laboratory. GIA is at the forefront in meeting this challenge, it tests every diamond to determine if it is natural. If it is found to be laboratory-grown, GIA issues a Laboratory-Grown Diamond Grading Report. As an added precaution and identification, GIA also laser-inscribes the diamond’s girdle with a report number and a statement that the diamond has been laboratory-grown.
The most common laboratory production methods are:
High-Pressure High Temperature (HPHT)
High-Pressure High Temperature is one of the two methods that is used to manufacture synthetic diamonds. This process involves placing a diamond seed in a controlled growth chamber with carbon in the form of graphite and a metal catalyst. Where under enormous pressure and high temperature, the molten metal flux dissolves the carbon source, which then precipitates and crystallizes on the seed to form the synthetic diamond crystal. Crystallization occurs over a period of several weeks to a month or more. This method imitates the way diamonds are formed in the Earth. The first commercially available “manmade” diamond was produced by General Electric in 1956.
Chemical Vapor Deposition (CVD)
Chemical Vapor Deposition is the other method that is used to manufacture synthetic diamonds. This process involves placing a disc with diamond seeds into a vacuum chamber at very low pressures, where it is treated with natural gas under a microwave beam. Due to this chemical reaction, carbon atoms are precipitated onto the diamond seed and stick to it. The seeded growth is now one carbon atom thicker. This process repeats itself endlessly for 21-28 days to replicate the crystal structure of the diamond seed crystal in three dimensions.
Flame Fusion or Verneuil Process
The Verneuil process, also known as flame fusion, was developed in the late 1800s by the French chemist Auguste Verneuil. It was the first commercially successful method used to manufacture synthetic gemstones and remains today the least expensive and most common method. This process involves dropping powdered chemicals through a high-temperature flame, where it melts and falls onto a rotating pedestal to produce a synthetic crystal. Commonly used for spinel, sapphire, and ruby.
The Flux Growth is one of the most expensive methods for manufacturing synthetic gemstones. This process involves dissolving a solid flux material with other components of the desired substance, and as the solution cools, synthetic crystals form within. Commonly used for emeralds but it can also be used for spinel, sapphire, ruby, and alexandrite.
The Hydrothermal Method is the only known method that can manufacture synthetic quartz. Hydrothermal means it is created in the water. This process imitates how quartz forms in nature, by creating an extremely hot environment where nutrients are dissolved in a water solution, and as the solution cools, synthetic crystals form within.
Crystal Pulling or Czochralski Process
The Czochralski Process or Pulling Method involves melting nutrients in a crucible, the synthetic crystal grows from a seed that is dipped into the melt, and then slowly pulled away from the melt as it grows. Commonly used for rubies, sapphires, garnet, alexandrite, and chrysoberyl.
Skull Melt Process
The Skull Melt Process is the only known method that can manufacture synthetic cubic zirconia. This process is similar to the Flux Growth, however, the solution needs to be extremely hot. In order to contain this hot solution, a “Skull cap” is created, meaning the outside of the vessel is water-cooled to form a solid crust which then contains the melt. As the solution cools, synthetic crystals form within.