These synthetic diamonds are created starting with “seeds.” The two techniques of creating LGD, high pressure, high temperature, and chemical vapour deposition, according to MS Ramachandra Rao of the Department of Physics at IIT-M, begin with the seeds, which are diamond ‘Type IIa’ crystals with no nitrogen or boron impurities.

Type IIa diamonds, which make up just 2% of naturally occurring diamonds, are extremely valuable. Rao, whose lab will lead the research, said that just a few of businesses have the capacity to create mother seeds.

In India, there is no recognised source for high-quality mother seeds or the technologies associated with them. At the moment, it is imported from other nations in order to grow high-quality diamond.

According to Rao, businessline, in the next five years, research and development in the fields of technology related to diamond seeds in the nation will advance, leading to initiatives like the National Centre for Lab-Grown Diamond at IIT Madras, which would greatly reduce the import of seeds.

In the HPHT process, seeds are subjected to temperatures of 1,600 degrees Celsius and pressures around six gigapascals, together with carbon powder and a catalyst.

Under sub-atmospheric pressures and temperatures of around 1,100 degrees Celsius, the CVD process breaks down molecules of a carbon-rich gas, such as methane, into carbon and hydrogen atoms in a sealed chamber. The gas is then applied to the seeds, creating a diamond with a square shape.

Which method is superior is a topic of ongoing discussion. Both are required, according to Rao. The HPHT process is highly expensive because to the energy used and equipment required, and it yields diamonds that are generally yellowish or brownish yellow in colour with metallic impurities.

Because it operates at low pressure and moderate temperatures and necessitates less expensive equipment, the CVD process is much less expensive. Because the vacuum container in CVD only contains carbon and a small quantity of hydrogen, colourless crystals can form. If nitrogen or boron are added to the chamber, synthetic diamond crystals in either yellow or blue colours can form.

In order to improve the quality of CVD-grown diamonds or to give them other colours including yellow, yellowish green, green, pink, and blue, the lab-grown diamond industry also uses the HPHT method.

Natural diamonds were outpure by LGD. Rao stated that while we can routinely grow good quality defect-free diamonds in laboratory, just 2% of naturally occurring diamonds are defect-free.

High purity diamond, which can only be manufactured in a lab using CVD and HPHT techniques, is required for emerging technologies including high-power electronics, 5G/6G base-station electronics, sensors, magnetometry, and quantum computing.

Regarding price, Rao stated that “LGD of less than one carat size is three to four times cheaper than natural diamond.”