Synthetic diamonds are diamonds grown in a laboratory rather than being found (i.e. mined) in nature. They are real diamonds. They have the same chemical composition and crystal lattice structure as those found in nature. But they are grown in a laboratory using one of two different methods. The High Pressure High Temperature (HPHT) method mimics the way diamonds are grown naturally in the earth’s mantle about 100 miles beneath the surface of the earth, where high temperatures and pressure transforms carbon into diamond. The HPHT laboratory method uses big presses to create the heat and pressure necessary to do the job in a much shorter period of time.
The other method is called Chemical Vapor Deposition (CVD). It uses microwaves to bombard a carbon infused cloud which causes carbon to rain onto a natural seed crystal and grow into a diamond. This is a relatively new technology.
Diamonds have been grown in laboratories for both experimental and industrial uses since the 1970s. These diamonds were industrial grade and the labs had difficulty growing diamonds that were large enough and high enough quality to be used in the jewelry trade. Growing diamonds in the near colorless range that the jewelry trade demands was especially challenging. That, however, is changing.
Rapaport magazine reports that the New Diamond Technology facility in St. Petersburg, Russia produced a 60 carat rough diamond in 2015 using their HPHT method which set a record as the largest laboratory grown diamond ever. They also produced in 2015 a 32.26 carat, colorless, high quality rough diamond from which was cut a 10.02 carat square emerald cut diamond which has graded out at E color and VS1 clarity.
The NDT facility has over 50 HPHT presses which can produce 5000 carats per month. Up to 16 colorless crystals weighing 6 to 10 carats each can be produced in each press in a cycle taking 10 to 12 days on average according to the Rapaport report.
In addition, there are many new players in the diamond growing business. Labs in China, Germany, India, Russia, the United States and Taiwan are growing diamonds up to 2 carats polished and in very good qualities. These diamonds are now moving into the jewelry trade pipeline and will present challenges to jewelers who will need to be able to identify them. Obviously, there will be big trouble for any jeweler who unwittingly sells a lab grown diamond without identifying it as such.