There are two growing methods used for creating diamonds in the lab; the HPHT (High Pressure High Temperature) method, and CVD (Chemical Vapor Deposition)
HPHT (High Pressure High Temperature)
Replicating the exact conditions where diamonds naturally deep in the earth’s depths, a microscopic diamond seed, pure carbon, is placed in a sealed chamber and exposed to extreme pressure and temperature. Heat and extreme pressure are applied (temperature is in excess of 4,700°F (2,600°C) and extreme pressure of more than 50,000 atmospheres) and once these optimum conditions are reached, the carbon seed will dissolve into a molten catalyst. This will be carefully cooled over a number of weeks (6-10 approx.) during which time the carbon atoms will gradually build onto the diamond seed to create a new diamond. This method requires the utmost precision, with no rooms for fluctuation in conditions at each highly critical stage of this process, to ensure the diamond is of gem quality. At the end of the process, new the lab-grown diamond will be cut and polished in exactly the same way as a mined diamond.
CVD (Chemical Vapor Deposition)
A diamond seed is placed in a vacuum chamber with pressure applied to a hydrocarbon gas. Typically, methane and hydrogen, these gases are then heated to an extremely high temperature, resulting in the decomposition of the hydrogen to form pure carbon atoms. The release of the carbon atoms then drop and attach themselves, much like drops of dew, to the original diamond seed. Gradually these droplets build layer by layer to form a new gem. Once formed, the new diamond will then be cut and polished in exactly the same way as a mined diamonds.
Choosing a diamond that is grown in a lab rather than mined from the earth is choosing to say no to environmental harm and exploitation, and saying yes to ethical and sustainable diamond production.