Colour is one of the four factors (4C’s) in grading a diamond, both lab grown and mined. Diamond colour evaluation is actually based on the absence of colour, a chemically pure and structurally perfect diamond has no hue. Many of the colour distinctions are invisible to the untrained eye which is why the Gemmological Institute of America and other labs use the D-to-Z diamond colour-grading system. With this they compare the diamond with established master stones under controlled lighting conditions. These distinctions make a huge difference in diamond quality and price so it’s important to get an expert opinion.

It’s actually incredibly rare to find a diamond that completely lacks colour. Diamonds with a poor colour grade can appear yellow, instead of the desired brilliant white but they can also be found in any naturally occurring colour, including pink, yellow and green. D is the best grading you can get as it lacks all colour.

Lab grown diamonds can share the same colour flaws as mined, as the mining process is replicated in a laboratory the same way. There are actually a wide range of colours that depend on the lab’s level of technology. Some have the knowledge and tech to create colourless grades, others do not. However, the technology is constantly developing, unlike the unpredictable mining process. Lab grown diamonds are graded in exactly the same way as mined diamonds.

HOW IS COLOUR GRADED?

The first official grading (or rating as it is less commonly called) of Diamonds was by the London Diamond Syndicate, in order to sort through rough Diamonds for sale. Up until the 1940s there were many different colour systems used by diamond traders, for example the first three letters of the alphabet, numbers and Roman numerals. These often led to confusion, inconsistencies and inaccuracies. 

In order to avoid confusion and create an accurate international system, the Gemmological Institute of America (GIA) introduced a fresh colour scale, which is now the accepted industry standard for grading diamonds.