If you know a thing or two about diamonds, you must be familiar with the 4 C’s. One of the C’s stands for colour. Coloured diamonds are found in nature too but they are formed under the Earth naturally due to some chemical changes in their structure. However, synthetic or man-made diamonds are made differently. All man-made diamonds are made using either of the two main methods: HPHT or CVD.

• High Pressure High Temperature (HPHT) method

As the name suggests, this method uses a high amount of pressure and very high temperatures to make the diamond. First, the diamond seed is placed inside the heating chamber. Then it is subjected to temperatures as high as 1500 °C and pressure as much as 870,000 pounds for every square inch.The heat causes the diamond seed to merge with the carbon and then the diamond is formed.

• Chemical Vapour Deposition (CVD)

The CVD is slightly different but begins with the same step which is using a diamond seed. It is kept in a sealed chamber and then subjected to high temperatures of heat. Next, the chamber is flooded with carbon-filled gases such as methane or hydrogen. Once the structure of the gases breaks down, it ionizes with the carbon in the diamond seed and a new, bigger diamond forms. With CVD, the diamonds formed are considerably bigger than the ones made using the HPHT process.

Today we’re going to talk about how exactly these coloured diamonds are made.

The initial process of coloured diamonds Hatton garden making is the same where the HPHT or CVD is used. So the basic step is the white diamond which is then treated further to get the required colour. For every colour the process is different. The ‘colour’ element in the diamond is actually a glitch; it is a flaw in the making process that is either present naturally or deliberately introduced in the process to get the colour. The impurities in the elements give the diamonds their colour.

1. The diamond seed is placed in the sealed chamber that is specifically created for the purpose of making diamonds in a large factory.
2. Next, it is either treated with heat and pressure or carbon gases as mentioned above in order for the molecular structure to break down and the diamond to start forming.
3. The next step is crucial because it actually marks the introduction of a colour hue. Various chemicals or gases are then released into the chamber so as to form the colour. For example,
4. For yellow, orange and brown diamonds, Nitrogen is mixed with the carbon.
5. For blue colour, very small amounts of Boron are mixed.
6. Green diamonds are formed by exposing the white diamond to gamma radiation is small frequencies.
7. Red and pink diamonds do not need any separate element, but are formed when exceptionally high pressure is applied to the diamond seed.
8. There are other rare colours like black, violet, brown etc. that also require different chemical elements. But more or less the process is the same.

Colour diamonds are really popular in the jewellery market. Many people also prefer buying their engagement or wedding rings Hatton gardens with coloured diamonds instead of the traditional white ones.