Lab-grown diamonds are made of the same material as crude diamonds, from carbon atoms, and they have the same optical, physical and chemical properties.

An environment is created wherein diamonds form naturally. It fully replicates the conditions of natural formation of diamonds in the earth crust.

Each lab-grown diamond is grown out of a tiny diamond crystal or a diamond plate. It is then placed within a chamber which reproduces the natural growth process.

DIAMOND CREATION TECHNIQUES

HPHT (high pressure high temperature) denotes high pressure and high temperature; it recreates a natural environment within which a diamond forms and grows deep inside the Earth. The equipment used is capable of creating a pressure of up to 60000 Atm and a temperature of 2500 degrees Centigrade.

A tiny particle of a crystal is placed into a cell containing the elements required to grow a diamond, in the centre of the chamber. Under the influence of the constant temperature reaching 1300 degrees Centigrade and the pressure of up to 50000 Atm a transition of elements from their liquid to melt form takes place.

A cooling process will then begin to last several days; it enables the carbon atoms to adhere to a crystal particle. After the growth cycle ends, the cell is taken out from the HPHT apparatus. A new crude diamond is then removed and cleaned in the preparation for final cutting and polishing.

The entire HPHT growth process requires for the environment to be put under permanent control to ensure that the diamond will have a quality suitable for jewellery-making. Any change during the growth period may result in the diamond stopping to grow or in the appearance of any inclusions rendering the diamond unusable.

The growth cycle of each diamond needs to be finished, after which the HPHT chamber will be opened. And only then will it be possible to get to see the crude diamond, its colour, clarity and size.

In the framework of the HPHT three main tools exist that are used to measure pressure and temperature and that are required to produce lab-manufactured diamonds:

  • Bars Press - Bars Press is the most effective tool for the production of precious diamonds. It uses a combination of internal and external presses in order to expose the growth chamber to hydraulic pressure.
  • Belt Press - Belt Press is the core diamond growing technology. It may be large-scale and produce several diamonds per cycle, by using two big presses which are thrust together to create the necessary pressure.
  • Cubic Press - Cubic Press may be of large dimensions and may use six separate presses to create a pressure required for the growth of diamond crystals. It is also used to create diamond powder for industrial purposes.

CVD (chemical vapour deposition) - means chemical deposition of vapour form.

A CVD diamond grows in vacuum plasma reactors.

The CVD process utilizes super-pure carbon-rich gases in the growth chamber. The carbon-based gases, such as methane, are heated until they decompose which then makes it possible to separate carbon atoms within the gas./p>

These tiny carbon atoms depose onto diamond plates and accumulate in layers resulting in the formation of a crude diamond crystal.

Crystallization then takes place enabling the lab-grown diamond to mature during six to ten weeks.

The recent years have seen active research in the area of CVD. At present, there is a growing number of the diamond reproduction methods, some of which include:

  • Low pressure CVD (LPCVD)
  • Ultra-high vacuum CVD (UHVCVD)
  • Plasma-enhanced chemical vapour deposition (PECVD)
  • Microwave plasma chemical vapour deposition (MPCVD)

A crude stone is then cut and polished in line with the requisite standards to gain a beautiful and genuine diamond ready to be set in a jewel product.

Process of diamond formation within the earth

Diamonds formed beneath the earth’s surface 100 million to several billion years ago at the depth of more than 200 kilometers.

Under the external layer of the Earth where the temperature reaches the extreme values of 1200-1500 degrees Centigrade, and the pressure - 30-50 kbar, a mix of carbon-bearing and hydrogenous gases slowly oxidizes, with the transition of carbon into another graphite modification – that of a diamond.

Billion years after being buried at large depths, diamonds are brought to the surface with the kimberlite magma during the eruptions of volcanoes, when kimberlite pipes are formed – primary diamond deposits.

After that, crude diamonds are cut and polished in accordance with the requisite standards in order to receive a beautiful and genuine diamond ready to be set in a jewel product.

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