Diamonds that are dug up in the ground are formed naturally through a combination of heat, pressure, and time. Lab-grown versions, however, recreate this process in as little as four weeks. There are two main approaches: high pressure high temperature (HPHT) and chemical vapor deposition (CVD). HPHT diamonds are created in a closed chamber using high levels of heat and pressure, while CVD diamonds are placed in a sealed vacuum at a temperature of 800 degrees Celsius. "The longer the time in the vacuum, the larger the rough will grow," explains Jogia. CVD diamonds are type IIa, meaning they are purer diamonds that contain little to no nitrogen.
Essentially, lab-grown diamonds replicate nature's process in a controlled environment with a fraction of the environmental footprint. It's important to note that once the diamonds are formed, they are uncut and unpolished just like mined diamonds. "The process of readying them for jewellery is the same as what a mined diamond must undergo at that point," Chavez says. Translation: The diamond will then get assessed for the four Cs: cut, colour, clarity, and carat. The length of time for cutting and polishing depends on the use of material. "The cutter will decide if it's best to cut one stone or many stones from one piece of rough diamond material," Jogia says. Then, the type of cut — round brilliant, radiant, cushion, emerald, or oval — will be determined. And finally, each stone will be graded by an international lab.