Diamond Colour
Diamond Fundamentals

Diamond Colour

The GIA grades all diamond colours using a scale from D (colourless) to Z (slightly coloured). Find out which colour grades to choose and which to avoid, with the aid of a diamond colour grade chart and information from expert gemmologists.
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What is diamond colour?

Diamonds can either be categorised as ‘colourless’ or ‘fancy coloured’. Fancy coloured diamonds, like blue and pink diamonds, are not graded on a colour scale like colourless diamonds are. Colourless diamonds are graded from D, completely colourless, to Z, tinted light yellow-brown. Diamond colour grades between D to F appear bright, white and icy and are regarded as the best choice for diamond engagement rings– although are priced higher due to their rarity.

Diamond Colour Scale

As the GIA explains, ‘diamond colour actually means lack of colour’. A high diamond colour grade is determined by the lack of colour present within the diamond, while poor colour grades can appear with a yellow or brownish tint. Using the diamond colour scale below, notice the very subtle difference in colour between diamonds graded D to F colour. Then consider the difference between G to H colour, where you’ll start to see a yellow tint, strengthening in intensity right down to Z.

How diamond colour grade is determined

At Celestara, we work with diamonds independently graded by the GIA, who provide a globally-renowned, highly accurate grading service. GIA diamonds are colour graded upside down to minimise light interference, and placed on a pure white background before being compared to master stones - until they find the perfect match. If a diamond looks between two grades, for example F and G, it will be awarded the lesser grade, in this case G (this may be referred to as a G+ colour grade).

What causes the trace colours in diamonds?

A poor diamond colour grade will appear slightly yellow, brown or even greenish in tone. This is because trace elements can be found within the pure carbon diamond that encourage the presence of colour. Yellow and brown tints are caused by traces of nitrogen. The stronger the colour, the greater the presence of nitrogen.
Some fancy coloured diamonds also contain trace elements that cause their colour, like boron in blue diamonds. Some, like pink diamonds, are coloured due to the crystal structure - which in this case absorbs most colours in the spectral range, emitting on a red-pink light.

What’s the best diamond colour grade to choose

A diamond’s colour grade is one of the most visible and apparent grades of all. A poor colour grade will be noticeable to the naked eye (unlike, for example, clarity grade which requires magnification). Gemmologists advise considering only D to F colour diamonds. D to F colour diamonds are the rarest of colourless diamonds, which is reflected by their pricing - so if you’re on a tighter budget, you may want to consider G to H colour grades. Any lower than H, diamonds appear yellow or brownish in tint.
If you choose a yellow gold or rose gold setting, you can afford to look at G and H colour diamonds. A platinum setting, however, will contrast and bring attention to poor colour grades, so we advise sticking between D to F for platinum rings.
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