Yellow Diamond

By Author: elvaflorence
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Ever wonder how Man Made Diamonds are created?

There are two major ways that man made diamonds are fashioned.

The high pressure, high temperature process simulates conditions found deep within the earth, where diamonds are formed naturally. A belt press was the 1st successful design. This design has two anvils that press together which enable it to grow several diamonds in one cycle. These presses are most often used for industrial diamonds and powder. A cubic press utilizes 6 different anvils pressing onto a cube. These presses are usually used to produce industrial diamond powder. A BARS press was developed by Russian scientists. It makes use of 6 inner anvils and eight spherical outer anvils to apply hydraulic pressure to the growth cell. One cycle of the BARS machine makes one diamond crystal. These BARS presses are currently, the best process for growing relatively big gem-quality diamonds.

At the core of the HPHT machines is a growth cell. This cell consists of all the elements and materials required to grow the diamond. This includes a small diamond seed, highly refined and purified graphite (carbon) ...
... and a catalyst of mixed metals and powders that facilitates the diamond growth. The growth cell is placed at the center of the machine and is heated to over 1,300 degrees Celsius and over 50,000 atmospheres of pressure is applied. As the temperature and pressure increases, the catalyst turns into a molten metal solution. Once the ideal conditions are reached, the graphite dissolves into this solution. Through a controlled cooling process over the course of many days, the carbon atoms gradually build upon the crystal structure of the diamond seed. The diamond normally grows in a truncated octahedron or a hexa-cubic shape, depending on parameters of the growth process. Once the machine runs its full cycle, the growth cell is removed. The brand new diamond is cleaned and able to be cut and polished, much like any other rough diamond. Throughout the growth, the temperature and pressure need to be maintained within an extremely strict set of parameters. If there is any fluctuation, the diamond can either stop growing, or become so heavily included, the usable gem-quality size can be quite limited.

Different colored diamonds grow at different rates, which is why the size availability varies based on the color.

Chemical vapor deposition is a very different process from high pressure, high temperature, though they both ultimately grow diamonds. The environment inside a CVD machine is a tiny percentage of 1 atmosphere of pressure. Carbon-based gasses, commonly methane, are added to the environment and are heated to many hundreds of degrees Celsius which will cause the gasses to break apart and release their carbon atoms. The carbon then "rains" down onto a diamond substrate, which is where it slowly grows in layers (a few micrometers per hour) as a crystal. This technology is best fitted to applications utilizing thin layers of diamonds, such as optics and semiconductors. CVD is capable of creating gem-quality diamonds, though the size of the polished diamond is limited by the thickness of the diamond wafer.

Visit d.neadiamonds.com to discover more about man made diamonds.

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