Diamonds are a girl’s best friend, and one of the world’s most prized natural materials—but what about lab-grown diamonds? Popularly marketed as cultured, engineered, or synthetic diamonds, these gemstones are man-made in a lab, rather than the process of natural diamond creation, which takes millions of years, the mining of which has been linked to having less than preferable environmental and social consequences.
How Are Lab-Grown Diamonds Made?
According to the Gemological Institute of America (GIA), there are two main processes used to manufacture lab-grown diamonds which date back to the 1950s: High Pressure, High Temperature (HPHT) and Chemical Vapour Deposition (CVD).
Both processes start with a “diamond seed”, a tiny diamond fragment that’s about as thick as a strand of hair. HPHT involves mimicking the environment in which diamonds are naturally formed within the earth's crust. This process can even improve the colour and clarity of a low-quality mined diamond. It can also be used to change the colour of a diamond into pink, blue or yellow. After this process, the stone is sold as a “treated diamond”.
CVD is a newer technique involving lower temperatures and pressures than HPHT. Gas containing carbon is pumped into a vacuum chamber that is heated and deposits onto the diamond seed. These carbon fragments layer and crystallise as the lab-grown diamond. Both processes take a few weeks, but the longer they are allowed to grow, the bigger the diamond will be.