The 4Cs - Diamond colour

Colour is very important to me because that’s one of the first things you see when you look at a Diamond. So, let’s look more into this. Diamonds fall into two types of colour grading systems. A diamond that is within the D-Z colour scale and a coloured diamond that is graded on its colour presence in a diamond.


Here is a little history on the GIA’s colour-grading System “In the 1950s, GIA established a colour-grading system for Diamonds. Because many of the colour-grading systems that came before it used vaguely defined trade terms. GIA wanted its system to clarify the colour-grade category At first, GIA planned the system so that only jewellery professionals would use it. They started the scale with the letter “D”, hoping that the letter’s poor reputation in the American school grading system would keep it from being used with customers. Today, professionals and consumers alike use the GIA Colour Scale. It has maintained its reliability and become the most widely recognised and well-respected colour-grading systems in the world.”


So, enough history, let’s talk Diamond Colour!

First, we are going to look into the D-Z scale. My favourite too! BTW did you know my initials are also DZ? How Spooky! Diamonds in the D-Z colour range’s value is based on the lack of colour, making Colourless diamonds the rarest! The GIA Colour Scale begins with the letter “D” - Colourless and continues through the alphabet to “Z” - light yellow, brown or grey. A Diamond’s colour grade is based on its tone and saturation and requires an assessment of its absence of colour. This means that the less yellow, grey or brown there is in a Diamond, the higher the colour grade. As you can see from the GIA’s colour scale below, the scale is divided into Colourless, Near-Colourless, Faint, Very Light and Light ranges.

Image by GIA

Let’s break it down!


D and E diamonds have virtually no colour, and an F has a nearly undetectable amount of colour that only shows in the face-down position. The difference in these grades are very slight and almost indistinguishable in diamonds smaller than 0.25ct. Diamonds in this colour range are extremely rare and valuable.


These grades are near-colourless! Diamonds graded as G-H-I or J look colourless face-up and nearly colourless face-down. They have slight traces of colour that aren’t noticeable to the untrained eyes when the stones are mounted. These Diamonds are the most popular because of the combine fairly high colour with somewhat lower prices.


Diamonds in the K-L and M scale, show very faint colour face-up and face-down. When mounted, and depending on the type of setting they are set in, small diamonds look colourless, but large ones show a slight tint of colour.


N to R diamonds appear very light yellow, brown or grey face-up and face-down, even when they are mounted in jewellery.


S through Z diamonds are light yellow, brown or grey. They show substantial colour face-up and face-down, loose or mounted. Once a diamond goes beyond the Z colour range, it’s classified as a Fancy Light, which causes the price to rise.

Video by GIA



The Difference between the D to Z scale can have a big impact on the price of the diamond. The most significant jump is between the D to E grades.

A 1.00ct. D-Flawless Diamond can cost over 50% more than an E colour of the same size and clarity. In all honesty to the untrained eye, it’s almost impossible to tell them apart.

Did you Know? For grades D-N, the grader assigns a single letter grade and from O-Z - a two letter grades. For example, O to P, Q to R, S to T and so on.


Customers Pattern

I’ve noticed a pattern with clients in the last few years. Customers are under the impression that “D” colour is the “BEST.” I can’t entirely agree with this statement as a “BEST” Diamond is very personal to each client. I like using the rarity scale rather than the Best to Worst. When a customer is inquiring about the colours of diamonds in the D-Z scale, I like to use the phrase “Warmer tones.” An example of a client asking me to explain the colour scale. “This is the GIA colour grade scale, as you can see the rarest colour or lack of colour is “D” this is extremely rare and very valuable in diamonds. The furthers you go down the alphabet the warmer tones you can see in a diamond. I don’t like to put them in a Best to Worst as every diamond is unique to you (the customer) some people prefer more of a warmer tone like the I-J-K but most would pick a G-H.”

This is my way of explaining the colour grades to customers without giving them too much information as this could be overpowering. But when they ask questions, you always have to be on full disclosure. Remember clients are visiting your store to purchase a ring and to educate them a little, not to be starting a new career :) If you know what I mean.

Fun Fact: Once I sold a diamond ring to a couple on a letter basis alone. The client’s name was Holly so, they picked an H colour Diamond.

Did you know? Most Diamonds found in jewellery stores today are from colourless to near-colourless, with slight hints of yellow

The Coloured Diamond Scale

The grading of coloured diamonds is a complex and specialised process. Although the human eye can differentiate among millions of colours, GIA recognises just 27 hues of colour grading diamonds. Each of the 27 hues represents a range of colours. Those hues consist of basic colours like red, blue and green, and mixed colours like orange-red, green-blue, and greenish-yellow. In the GIA system, the predominant hue is stated last. This means that terms such as “yellow-green” and “green-yellow” represent different hues. GIA uses the following grade terms to describe the combined effect of tone and saturation on diamonds’ hue.