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How Are Diamonds Formed?

  • 3 min read

Rough Diamond

 

 

There is a widespread belief that when coals are put under extreme pressure, they turn into diamonds. Although this concept is often seen as inspirational, it's actually far from the truth!

Diamonds are actually formed when carbon is exposed to extreme heat and pressure levels. These extreme conditions cause carbon atoms to bond in a unique way that results in a diamond’s unique and rare structure. 

This is a process that traditionally took place naturally, within the earth. However, within the last century, scientists have been able to re-create these conditions of extreme heat and pressure in a laboratory, resulting in lab-created diamonds.

To start with, let's take a look at how diamonds were originally formed.  

 

How Are Natural Diamonds Formed?

Natural diamonds are created when carbon dioxide is exposed to the extreme conditions that exist approximately 90 miles (150 kilometres) beneath the earth’s surface over millions, or even billions, of years.

When a volcanic eruption occurs, the rushing magma tears pieces of diamond free from and carries them to the surface of the earth. This is where the diamonds remain until they are mined, polished, and eventually, used commercially. 

No two diamonds are the same, but some diamonds are even more unique than others. Diamonds that fall outside of the usual diamond colour scale are known as ‘fancy diamonds' and can be found in shades of red, pink, blue and green. These diamonds are the rarest and most valuable.

These uniquely-coloured stones are formed when foreign particles are trapped within the diamond during the diamond’s crystallisation process, altering the chemical process of formation, and changing the final appearance of the diamond. This results in rare, unique, and exceptional-looking diamonds.

 

Fancy Yellow Diamond

 SOURCE: GIA

A fancy coloured yellow diamond, which is the result of high levels of nitrogen being present while the diamond was being formed.

 

How Are Lab-Grown Diamonds Formed?

In the 1950s, scientists were first able to replicate the extreme temperature and pressure conditions that lead to the formation of a diamond within the earth. As a result, we are now able to create diamonds in a lab.

The two methods used to create manmade diamonds today are High Pressure-High Temperature (HPHT) and Chemical Vapor Deposition (CVD).

 

1. HPHT
When the HPHT method is used, a tiny sliver of a diamond known as a 'seed' is put into a piece of carbon. The carbon is then put under the same pressure and heat conditions that can be found 90 miles beneath earth's surface, which eventually melts the carbon and forms a diamond around the initial diamond seed. The new diamond is then carefully cooled and can now be polished and cut, just like a natural diamond.

 

2. CVD

With the CVD method, a diamond seed is placed inside a heated chamber, and the chamber is then filled with carbon-rich gases. The molecular bond of these gases are then broken down so that pure carbon begins to stick to the diamond seed and a new diamond forms. At this point, the diamond can be treated to enhance or change its colour.  

The biggest difference between a CVD and a HPHT diamond is the way they are grown. CVD diamonds often have lower colour and clarity until they are treated, but a CVD and HPHT diamond of the same colour, cut, clarity and carat weight will be identical in their quality. 

 

Does It Matter How My Diamond Was Created? 

Many people shopping for engagement rings question the difference between a lab-grown diamond and a natural diamond. Although in everyday language some people may use the word 'real' to describe natural diamonds, make no mistake – lab-grown diamonds are every bit as real as diamonds formed within the earth, sharing the same qualities and characteristics. 

At the end of the day, the decision of whether to buy a lab-grown diamond or a natural diamond is ultimately personal, and can depend on factors such as budget, personal style, and personal values. 

Are you considering a lab-grown engagement ring? Let us know on Facebook, Instagram, or down below in the comments section!