In July 2018 the Federal Trade Commission issued a new guideline stating that a diamond is a diamond, irrespective of whether it was produced in a laboratory or formed in the ground.
Rather than forming in the depths of the Earth, a lab-grown diamond is created in the controlled environment of a laboratory. They are created using extreme pressure and heat inside a machine rather than deep inside the Earth. There are two ways to grow a diamond. Both involve starting with a microscopic diamond seed.
High Pressure High Temperature (HPHT)
The first lab diamond was made using a High Pressure High Temperature (HPHT) system, where the seed is then placed with pure graphite carbon and exposed to temperatures of about 1,500C and pressurised to approximately 1.5 million pounds per square inch in a chamber. Carbon atoms attach to the seed, causing it to grow, very slowly, over a period of several weeks.
Chemical Vapour Deposition (CVD)
More recently, another way to grow a diamond was discovered, called Chemical Vapour Deposition (CVD). This involves putting the seed in a sealed chamber filled with carbon-rich gas and heating to around 800C. Under these conditions the gases begin to “stick” to the seed, growing a diamond carbon atom by atom. This process creates larger carat weight rough diamonds between three weeks and a month, it is then sent for cutting.
Thanks to the short and transparent supply chain, lab-grown diamonds are priced lower than natural diamonds by up to 40% less.