Diamond Colour Chart Explained: What Every Buyer Should Know

Looking to purchase your ideal diamond for your engagement ring and fine jewellery? Read our detailed guide to learn more about the diamond colour chart about how diamonds are graded from colour D to Z.

One of the crucial aspects used to determine the quality of a diamond is their colour. Contrary to what you may expect, diamonds are not graded for the presence of colour but for the absence of colour. The highest quality and rarest diamonds are both flawless and colourless.

When searching for a diamond for your engagement ring, colour is one of the 4C’s you must consider alongside cut, clarity and carat weight.

Our guide below explains all you need to know about diamond colour grading, including how to interpret the GIA diamond colour chart.

The Basics of Diamond Colour Grading

Diamond colour grades refer to the faint yellow hues naturally occur in diamonds. During formation of a diamond, it's common for nitrogen to become trapped within the crystal structure, causing a faint yellow hue. Colourless D colour diamonds are pure carbon, whilst a Z colour diamond include trace amounts of nitrogen (even less than 1% can cause a noticeable yellow colour)

Colours of Diamonds

Most clients are familiar with white diamonds (aka. the colourless diamonds within engagement rings and fine jewellery) and the GIA diamond colour chart is a reference for white diamonds only.

Natural and lab grown diamonds do come in a variety of spectacular and vivid colours such as pink, blue, green and red - but their quality is not measured against this. Coloured diamonds all have their own standards for grading from GIA (Fancy Light, Fancy Intense, Fancy Vivid etc).

What is the GIA Diamond Colour Chart?

Developed in the 1950’s by the Gemological Institute of America (GIA) produced the 4C’s diamond chart. A standardised scale to describe the colour characteristics of a diamond.

The scale begins with the letter D, denoting the highest grade (colourless) and goes down to the letter Z (yellow). This internationally accepted grading appears on all GIA, GCAL and IGI diamond certificates.

The most admired diamonds are colourless, as colourless diamonds are the purest and able to produce the brightest and whitest sparkle!

Before we discuss the technicalities of diamond colour grading, you must also remember that diamonds are always graded as a loose stone prior to being set within an engagement ring.


image credit: GIA

The GIA Diamond Colour Scale

The GIA diamond colour chart is categorised into five main groups used to describe the absence of colour or yellow hue within the diamond. They are:

• Colourless Diamonds - graded D, E and F
• Near Colourless Diamonds - graded G,H,I,J
• Faint Yellow Diamonds - graded K,L,M
• Very Light Yellow Diamonds - graded N,O,P,Q,R
• Light Yellow - S,T,U,V,W,X,Y,Z
  
  

Diamond Colour Grade

The GIA grading scale establishes that:

• D colour diamond - contains no colour
• E colour diamond - appears colourless similar to the D colour diamond to the naked eye
• F colour diamond - also appears colourless and can only be distinguished by a trained gemologist 
• G colour diamond - appears mostly colourless to the naked eye  
• H colour diamond - appears colourless but may have a faint yellow tint under bright light
• I colour diamond - have a slight yellow tint noticeable against white backgrounds

image credit: GIA

Understanding colourless diamonds

Diamonds are always colour graded upside-down under consistent and standardised lighting. Never within a ring or piece of jewellery. This produces the most accurate assessment and precise grading for the diamond.

Expert gemologists use a master set of stones, representing each of these colour grades, as a comparative tool when assessing each diamond to establish their grading.

Diamonds graded D, E or F are barely distinguishable from one another visually. Only trained gemologists can decipher these colour discrepancies with their expert observation techniques.

From referencing the diamond colour grade on the diamond certificate, you can identify where the diamond you’re viewing falls on the colour grading chart. This can assist in your selection process for the diamond for your engagement ring. Generally speaking the higher the colour grading the more desirable and more expensive the diamond, and the lower colour grading the lesser desirable and therefore lesser value the diamond.

However, it isn’t always this straightforward. As diamond colour is only one aspect out of the 4C’s to determine their quality. When choosing a diamond - also pay attention to other diamond’s cut, clarity and carat weight. Which can equally influence the diamond quality and its sparkle. A combination of all of these aspects contribute to a diamond’s value.

Impact of light on diamond’s colour

Lighting conditions can play a big role in influencing a diamond's colour as they are highly sensitive to their environments. In natural sunlight, a diamond’s brilliance and fire will be most evident. On a cloudy day, the diffused soft light will lessen their brilliance but showcase their inner clarity. Diamonds placed under artificial lighting such as LED lights, can take on cooler blue tones highlighting their sparkle and warmer incandescent lights will enhance their fire and rainbow flashes.

The time of day can also transform the colour appearance of a diamond. Golden hues of a sunset or sunrise can add a warm hue and glow to the stone, and a harsh midday sun can brighten a diamond bringing out their intense scintillation. This is why it is so important when expert gemologists colour grade a diamond they are placed under controlled lighting conditions to obtain the most accurate diamond colour grade.

Importance of the Ring Setting

The colour grade of a diamond can also be influenced by the metal in which it is set. The reflective properties of polished 18ct white gold can enhance a diamond’s appearance. In a finely crafted white gold setting, especially one where the interior of the claws and basket are highly polished, the metal will act like a mirror, amplifying the diamond’s beauty and minimising any perceived colour.

The reflective properties of polished 18ct white gold can make the subtle differences in colour grades almost indistinguishable. Consequently, a diamond set in 18ct white gold will affect the brightness of the diamond, enhancing their colour grade and sparkle. This is incredible to complement a diamond, yet proves incredibly difficult to produce an accurate colour grading within a ring.

How to Choose the Right Diamond Colour

Choosing the right diamond colour is essential in creating an engagement ring that perfectly reflects your style and preferences. As a custom jeweller, at JANAI we understand the subtleties of diamond colour grading - and our team is here to guide you through the selection process to help you choose the best diamond for your engagement ring.  In our showroom we have a vast collection of D, E and F colour lab grown and natural diamonds and can source your desired colour grade to suit your preferences and complement the setting and design you envision. We provide personalised advice and support to ensure you make an informed decision.

Let us assist you in creating your dream Engagement Ring in Melbourne! Request your appointment today by filling out the booking form below.