How are diamonds created…? A whistle stop tour

Most people are familiar with the story that diamonds are created over millennial deep in the earth ….but did you know that they can occur in nature in a number of ways? And did you know, it is of no coincidence that the majority of diamond mines are in Africa?

In this blog post, we will do a whistle-stop tour of how diamonds are created naturally and how these processes have been replicated in a laboratory to make created diamonds - as testament to manmade brilliance and ingenuity.

 

 

In nature, diamonds are formed under extreme temperature and pressure, atoms in their crystalline structure become tetrahedrally bonded (each carbon atom links to 3 other carbon atoms) to create a strong and stable lattice. Diamonds are created by intense pressure and heat in the earth of 900°C to 1300°C in combination with an extremely high pressure of 650,000 psi to 850,000 psi.

 

These perfect conditions are only found deep within the earth, with the majority of diamonds forming inside the earth’s mantle, under parts of the continental crust called cratons. Over millions of years the diamond crystals grow and slowly make their way to the surface via Kimberlite pipes. (These are carrot-shaped volcanic pipes rising from the upper mantle 100-300km beneath the crust.).

Hence, it is no coincidence that cratons are found in continents with extreme temperatures, like Africa and Australia, which are also significant producers of large diamonds with superior gemmological quality.

 

When the earth’s tectonic plates collide, one land mass is forced under another and this creates a so-called “subduction zone.”

If one of these plates carry rocks and materials rich in carbon content, they melt under high temperature and pressure to create diamonds. Some of them make it back to the surface due to plate movements while others may lie in place for millions of years before being brought to the surface via volcanic eruptions.

 

When an asteroid strikes the Earth’s surface, the epic collision creates a massive explosion of heat and pressure on the ground. Carbon based deposits in the impact crater can get turned into tiny diamonds in an instant.

As meteorites from outer space hit the earth’s surface, they deposit their contents which contain nanodiamonds from space.

 

 

There are 2 main methods of producing gemmological quality laboratory grown diamonds:

 

              HIGH PRESSURE HIGH TEMPERATURE

 

This recreates the earth’s natural geological processes through the application of intense pressure and heat onto diamond seed crystals.

 

 

This is a more modern method whereby diamonds are grown in a hydrocarbon gas mixture in a controlled environment.

The hydrocarbon gas (usually methane) is heated to elevated temperatures and broken down into its atomic state. The carbon atoms are then precipitated onto seed crystals and the rough diamond is grown layer by layer.

 

Besides lower temperatures, the CVD method doesn’t require high pressures and achieves higher growth rates than HPHT. As a result, CHELSEA ROCKS, only uses diamonds created by the CVD method as it is lighter on the environment?

 

At CHELSEA ROCKS, we celebrate laboratory grown diamonds as a products of mankind’s intelligence and innovation and believe that there is a diamond for every purchaser’s taste, budget and lifestyle. #shineon!