Creation of lab diamonds
Mined diamond forms when pure carbon is treated in extremely high temperature (up to 1,093 degrees celsius) together with crushing pressure over billions of years within Earth’s mantle.
Two methods are currently used to create lab diamonds: Chemical Vapor Deposition (CVD) and High Pressure-High Temperature (HPHT).
To create a CVD diamond, a thin slice of diamond seed placed in a sealed chamber and heated to around 426 degrees Fahrenheit. The diamond seed that is used in most cases is a HPHT produced diamond.
Plasma technology is used once the chamber is filled with certain type of gasses such as methane for example. In simple terms, plasma technology is a process that allows a matter to change its state when energy is introduced to it. In the case of the lab diamonds, the ionisation breaks the molecular bonds in the gases and the pure carbon adheres to the diamond seed and slowly forms a crystal until they form rough diamonds.
HPHT diamonds can be created using either a cubic press, split-sphere (BARS) press or a belt press. Using a belt press the generates pressure of over 1.5 million pounds per square inch with temperature above 2,000 degrees celsius, the pure carbon will melt and will start to form into a diamond around the diamond seed.
Difference between lab diamonds and mined diamonds
Since lab diamonds are grown in highly controlled environments, there are distinct conditions of how lab diamonds are formed compared to mined diamonds and this causes lab diamonds to present some features which from a pure gemological perspective could be differentiated to mined diamonds. One would need special equipment to be able to distinguish such differences.
Moissanites and Cubic Zirconias
Moissanite is a man-made, synthetic gem that actually has some diamond-like properties. It has a completely different chemical structure and different optical properties compared to a diamond. Another popular diamond simulant is synthetic Cubic Zirconias (CZ). It sparkles very well and is cheap to produce. Simulants are gems that look like a real, natural gem but are actually another material as they do not have the same chemical or optical properties of diamonds. Moissanites and Cubic Zirconias are diamond simulants and are far different from lab diamonds.
Grading and certification
Lab-created diamonds are graded and certified following the exact same process and standard for mined diamonds. Lab diamonds are sent to the same laboratories where mined diamonds are sent to be graded and certified. Some of the most popular diamond certification companies include IGI, AIG, and EGL.
Just like a mined diamond, a lab diamond's characteristic is evaluated using the 4C metric - cut, clarity, color, and carat. Each diamond is graded by the gemologists in the diamond certification companies and a diamond grading report is produced after complete assessment is done. For example, the IGI Laboratory Grown Diamond Report
provides the same information as the IGI Diamond Report but the color of the report is yellow. The Lab diamond is laser inscribed with the report number as well as the word "lab-grown".