Along with high pressure, the process involves high temperatures, usually between 2,200 to 2,800 degrees Celsius (4,000 to 5,000 degrees Fahrenheit). The combination of high pressure and high temperature causes the carbon atoms to rearrange into diamond crystals.

4. Growth Process: The carbon source material is placed in a growth cell along with a small diamond seed crystal. The high pressure and temperature cause the carbon atoms to vaporize and then crystallize on the lab grown diamonds seed, gradually building up a larger diamond crystal.

5. Cooling: Once the diamond has reached the desired size, the temperature is slowly reduced to stabilize the crystal structure.

6. Cutting and Polishing: The rough lab-grown diamond is then cut and polished by skilled gemologists to create the finished gemstone. The resulting lab-grown diamond has the same chemical composition (carbon) and crystal structure as a natural diamond.

Lab-grown diamonds produced using the HPHT method can vary in quality, just like natural diamonds. They can be graded based on the same factors as natural diamonds, including the 4 Cs: carat weight, color, clarity, and cut. Some lab-grown diamonds are virtually indistinguishable from natural diamonds to the naked eye.

HPHT-produced lab-grown diamonds have found applications in various industries, including jewelry, where they offer an ethical and often more affordable alternative to natural diamonds. Their quality and desirability have continued to improve as technology and production techniques advance.