The Process for Color Enhancing a Diamond

In nature, diamonds are created at extremely high temperatures and pressures in the mantel of the Earth, at a depth of around 140 to 190 kilometres.

In the laboratory, processes which would usually take thousands of years can happen in a mere few hours. The processes usually used today are Irradiation & HPHT. They also happen to be the two processes we use here at Lotus Colors. The color enhancement process in the world of diamonds plays a pivotal role in transforming near colorless diamonds into exquisite works of art.

Creating COLORed DIAMONDS with Irradiation

The most common process used for color enhancing a diamond consists of two steps : Irradiation and Annealment. Together they enable a nearly colorless DIAMOND to obtain a beautiful variety of colors.

What it does?

Natural color in a diamond comes from the presence of trace impurities in the stone or structural irregularities at its atomic level. Irradiation or HPHT promote changes in the stone’s atomic structure in the laboratory – with the same result: the diamond gains color. Irradiation or HPHT doesn’t actually ‘give’ a diamond color, therefore, but rather simply unlocks its color potential.

Irradiation –

Currently the safest way to irradiate diamonds is by using a machine known as a linear accelerator. This fires a pulsed beam of electrons at the diamond, which then disturbs the electrons of the diamond itself, causing them to be knocked loose and ‘captured’ by other atoms. The light absorbing structure of the gem is changed and, as a result, so is their color. This process is known as low energy electron bombardment.

Annealment –

Exposure to electrons gives diamonds a greenish blue or blue color. In order to get the whole multitude of colors, irradiation is followed by heating to an extreme temperature of around 450 C/850 F and upwards. We call this ‘annealment’ as it is done in an oxygen-free environment. This causes the stones’ atomic structure to rearrange yet again, resulting in a range of new colors. Irradiated color diamonds go through the annealment process, which mimics nature, since natural heating in the right environment can alter a diamond’s color as well.

Here at Lotus Colors, we use only low-energy electron methods of irradiation and annealment. More powerful methods using protons and neutrons can work faster, but these types of treatment may result in radioactivity in the diamond, so they’re best avoided. While irradiated color diamonds may raise questions about safety, they are rigorously tested to ensure they pose no health risks.

Colors Manufactured by Lotus Colors using Irradiation -

All our colors are manufactured using Irradiation - Aqua Blue, Sky Blue, Ocean Blue, Royal Blue, Pine Green, Ice Green, Emerald Green, Forest Green, Canary Yellow, Golden Yellow, Baby Pink, Rose Pink, Purple, Orangish Cognac & Reddish Cognac.

High Pressure High Temperature

The High Pressure High Temperature (HPHT) process is designed to precisely mimic the natural conditions in the mantel of the Earth where diamonds are created. The process allows the natural trace elements within a diamond to relax and to display their natural color. Highly sophisticated machines expose the diamonds to heightened heat and pressure resulting in the change of the color of the diamond. When HPHT Color Diamonds emerges from the machine, the diamond is initially covered in a frosty outer layer. After polishing, their newly attained beauty is revealed. Only diamonds of very high clarity can be used for this process, as any small feathers in the diamond will result in worsening or even chipping out of the diamond during the HPHT process.

Initially the primary colors created using HPHT were white, yellow, green & orange. Recently with the combination of both HPHT and irradiation, we have been successful in manufacturing some Baby Pink, Rose Pink, and Purple diamonds in limited quantities.

Colors Manufactured by Lotus Colors using HPHT –

Canary Yellow, Golden Yellow, Baby Pink, Rose Pink & Purple.