Naturally-formed diamonds are pure carbon, crystalised in the isometric cubic form beneath the earth’s crust. Lab-grown diamonds (LGDs), on the other hand, are manufactured in laboratories with either of the two methods — chemical vapour deposition (CVD) or high pressure, high temperature (HPHT) using a chemical composition.
As early as 1952, Union Carbide claimed that it had produced the first CVD diamond, while other producers made diamonds using the HPHT technology. These diamonds were primarily used in industries, especially in telecommunications and laser optics. But gem-quality laboratory-grown diamond was first made in the 1970s by researchers at General Electric. Around the same time, scientists at the Gemological Institute of America (GIA) conducted the first scientific study of LGDs.
LGDs have physical and optical properties similar to that of natural diamonds. A common eye can’t distinguish between a natural diamond and an LGD and it requires a trained gemologist and sophisticated equipment to differentiate the two.
The size, clarity, cut and colour of LGDs make them suitable substitutes to natural diamonds, especially when the availability of natural diamonds becomes scarce due to depleting reserves and escalating costs.
How are the lab-grown diamonds produced?
Unlike natural diamonds that take centuries or several millenia to be formed below the crust of the earth under extreme heat and pressure, the LGDs are made in laboratories using either the CVD or HPHT method. It takes less than a month to make a distinctively-shaped crystal.
The process starts with a seed — a slice of another diamond — on which the LGD is created. The HPHT method mimics the high-pressure, high-temperature conditions that occur under the earth to form a natural diamond. The seed and graphite carbons are exposed to extreme temperatures (1,500 degrees Celsius) and with extremely high pressures to make a LGD.
The LGDs made in China are mostly produced using HPHT method.
The CVD method is more popular in India. CVD is a chemical process in which the seed is heated up to 800 degrees in a sealed chamber filled with molecules of carbon-rich gas such as methane. These gas molecules are broken down into carbon and hydrogen atoms, which get deposited on the seed giving it a shape of square, tabular diamond crystal. This process also requires heat or irradiation to give the crystal a colour effect.
Are the lab-grown diamonds used in India?
Still at a nascent stage, the LGDs are gradually gaining ground in the country, while in other parts of the world the commercial marketing of LGDs started about 10 years ago.
In India, the share of lab-grown diamonds in overall diamond business is presently just 2-3 per cent. In India, lab-grown diamonds are mostly used for jewelleries and exports. About 80 per cent of the cut and polished LGDs are exported, while only 20 per cent are consumed locally.
Why is the government focussing on production of lab-grown diamonds?
In the latest Budget, Union Finance Minister Nirmala Sitharaman has abolished the Customs duty on imports of seeds used for manufacturing of rough lab-grown diamonds.
The move is aimed at boosting the exports of LGDs from India and also reduce dependence on imports for the key input, i.e., seeds and equipment.
The duty now stands nil from 5 per cent earlier. This is expected to encourage imports of seeds to manufacture rough lab-grown diamonds locally and reduce the imports. Notably, India imported rough LGDs worth ₹919 crore in December 2022, and ₹7,656 crore in April-December 2022, the data from Gems and Jewellery Export Promotion Council showed.
In order to boost research and development capabilities, the Centre has extended financial assistance to the Indian Institute of Technology Madras for a period of five years. This is expected to create an ecosystem for LGDs in India.
What is India’s export potential?
According to Gems and Jewellery Export Promotion Council (GJEPC) data, LGD exports from India in December 2022 stood at ₹844 crore, up 8 per cent from ₹779 crore in December 2021. For the April-December, the LGD exports were up 54 per cent year-on-year at ₹10,587 crore.
The US and Europe are the key markets for India’s CVD lab grown diamonds. With the government support, the industry expects India’s LGDs will be competitive globally.