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.
How are the lab-grown diamonds produced?
There are two processes followed by labs to create diamonds; High Pressure-High Temperature (HPHT) and Chemical Vapor Deposition (CVD).
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.
Sub-Types of Lab-Grown Diamonds:
Simulant diamonds
Simulant diamonds come closest to representing the natural diamonds, the difference is probably not visible to the naked eye.
Diamond Nexus Stimulants
These diamonds are produced from carbon mixed with additional ingredients. These stimulants have a triple lifetime guarantee due to their extreme durability.
Cubic Zirconia Stimulants
These diamonds are produced from zirconium dioxide. They are the least durable type of the stimulant diamonds, they also come at the lowest price.
HPHT diamonds
High pressure high temperature diamonds are made in an environment that is similar to the environment favourable for the production of mined diamonds.
Cultured diamonds
Cultured diamonds are created from scratch and built in an environment that represents the environment in the diamond mines.
CVD diamonds
The CVD diamond growth enables the growth to happen over various substrates and large areas. It also improves the control over the chemical impurities.
