Diamond Colour Grading: Explained

What Does Diamond Colour Mean?

Diamond colour shouldn’t be confused with coloured diamonds. The latter relates to actual colours, like pink, green, even orange diamonds which are all structural defects that take place whilst a diamond is forming in the earth. Diamond colour relates to the Gemological Institute of America (GIA) colour-grading scale for diamonds, which is also used by International Gemological Institute (IGI) who grade most Cullen Jewellery diamonds. Colour is also one of the famed 4Cs which determines the price of a diamond – the clarity, cut, colour and carat weight.

The D to Z of the Diamond Colour Chart

Simply put, the colour grading scale determines the lack of colour in a diamond, with D representing colourless, and Z being a light brown or yellow tinge. The slight differences between each colour grade aren’t visible to an untrained eye and are graded under controlled lighting settings. Yes, many of these colours are undetectable to the naked eye, but they make a huge difference to the price of the stones in the market.

D, E and F-grade diamonds are all essentially colourless. Finding natural diamonds in this condition is extremely rare, this rarity results in the price of these grades being the highest of all diamonds.

G, H, I and J grade diamonds are near colourless, so have very little colour and when mounted on jewellery - typically in yellow or rose gold, will appear colourless. Insider tips like this are why understanding the details of diamonds can save you money if you take into consideration the bigger picture, and why it's important to be looking for a ring with a jeweller who isn’t just trying to get you to part with the most cash..

K, L, and M grade diamonds have a faint colour, and in a big carat weight, the naked eye will be able to see the difference between these and the previous colour grades. If you’re looking to make a more intricate design using minuscule diamonds, you can put these to use as they can appear colourless in very small carat weights - and using D, E or F diamonds here would be an unnecessary waste of money.

N-R grade diamonds are a very light colour, and the further you move down the scale, the more easily you’ll be able to see the yellow tinge. As you get to the light colour grades, S-Z, the diamonds will have a warmer hue, like a yellow colour.  If you like canary yellow diamonds, these can be a great money-saving alternative and will pair beautifully with a yellow gold band.

What About Lab-grown Diamonds?

Lab-grown diamonds are also available in the same colour range as mined diamonds, though a D colour lab-grown diamond will still be significantly cheaper than the same if mined. That’s not to say you don’t get to participate in the fun of coloured diamonds if that’s what you’re looking for. Lab-grown diamonds can come in yellow, blue and pink – we spoke about them here.

For those who would rather not worry about researching the clarity and colour of natural diamonds, to determine whether you’re paying a fair price, lab diamonds are generally more of a safe bet - though these can also deviate in quality. The quality of a lab diamond can be based on how it has been cut, so still be sure you’re going with a jewellery you trust.

The interesting thing about the diamond colour chart is that it's purely a way for the industry to price diamonds, and shouldn’t be how you choose which diamonds to put in your ring. Instead, look at the bigger picture, what size is important to you, what colour do you like? If you have a budget in mind, choosing a faint colour will get you a bigger stone than choosing a colourless diamond. The same consideration goes for what metal colour band you’re opting for. A platinum or white gold band will look best with a colourless or near colourless diamond, whereas a faintly yellow diamond will look beautiful against a warm-toned metal like yellow gold or rose gold.

These differences and preferences cannot be overlooked, so be sure you go to a jeweller who is willing to listen and find you the best possible ring, at the best price.