How are Laboratory-Produced Diamonds Created?

Discover the two methods that help you answer the question, “how are lab-grown diamonds made?” CVD and HPHT. Learn how scientists have developed a technique to imitate the natural development of a diamond in a laboratory and how these processes generate genuine synthetic lab diamonds similar to those found in nature.

How are diamonds created in a laboratory?

Laboratory diamonds in a controlled environment replicate how diamonds are formed organically beneath the Earth’s mantle. CVD (chemical vapour deposition) and HPHT (high-pressure high temperature) are the two techniques used to make lab diamonds (high-pressure high temperature). Both produce high-quality, genuine diamonds similar to those found in nature. In a few weeks, the carbon gas ionises, and the particles adhere to the initial diamond slice before crystallising into a formed diamond.

HPHT:

When the HPHT method gets used, a piece of diamond seed gets inserted into a piece of carbon. The carbon is then compressed to roughly 1.5 million pounds per square inch using a belt press, cubic press, or split-sphere (BARS) press. Furthermore, the carbon gets subjected to temps exceeding 2,700 degrees Fahrenheit. The pressure and heat dissolve the carbon to form a diamond around the original diamond seed. After that, the new forms of the diamond get meticulously cooled.

CVD:

CVD, like HPHT, employs a tiny diamond seed (often an HPHT diamond). This seed is in a sealed chamber heated to over 1,400 degrees Fahrenheit and with carbon-rich gases (typically methane and hydrogen). These molecules get ionised into plasma via a process comparable to lasers or radiation. This technique tears down the gas’s molecular bond. When the molecular link gets disrupted, pure carbon starts to adhere to the seed and forms a new diamond. Additional procedures (heat or irradiation) may get used after the diamond forms to improve or alter its hue.

Plant the germ:

The HPHT procedure starts with a seed crystal, which is a tiny diamond fragment. It is a press chamber with a metal catalyst, such as nickel or iron. On top is a lump of carbon, such as graphite.

Apply some weight:

The compactor raises the temperature of the chamber to a blistering 1,600°C. It then applies pressure with metal anvils. The force and temperature must get sufficiently elevated to dissolve the metal catalyst.

Atoms build-up:

Molten metal transports carbon atoms from graphite to the seed crystal. Carbon atoms gradually accumulate around the crystal to form familiar multi-sided formations.

Sand and shine:

After cooling, the diamond is sliced and polished, just like nature’s best. The cut, colour, carat, and purity can then get evaluated.