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When most of us think of diamonds, we tend to think of a pure and colourless stone with no hue. But the truth is, diamonds come in a wide and diverse range of colours.

The vast majority of diamonds are not pure, colourless stones, but are in fact gems with tints of yellow or brown. Typically, the term “diamond colour” actually refers to an absence of colour, as a lack of colour is one of the four main criteria used to assess a diamond’s overall quality.

The Four Cs

The now universal criteria for judging a diamonds overall quality are the ‘four Cs’, of colour, clarity, cut and carat. Two of these criteria, clarity and colour, are graded on a scale devised more than 50 years ago by the Gemological Institute of America as a means of qualifying the rarity of a diamond.

As well as grading colourless diamonds on a scale of D to Z, with Z being obviously yellowish or brownish, the GIA also grades diamonds that are more coloured or rare and desirable. We call these, fancy coloured diamonds. GIA developed grades based on the Munsell colour grading system to rate the attractiveness of colour within a stone.

Hue, Tone & Saturation

The hue, tone and saturation of a diamond also have an impact on its value. We use ‘hue’ to describe a gem’s overall body colour, and ‘tone’ to indicate the lightness or darkness of that colour. Tones can range from clear (without colour) to black. A diamond’s saturation refers to the intensity of its colour. A more intense gemstone colour, like the brightest red ruby or the bluest sapphire are those with the best saturation. A pure colour, free from any traces of brown or grey. Holloway Diamond’s top fancy coloured diamonds are rated with either excellent or very good saturation for a vibrant, bright colour.

When we describe a diamond’s tone we are referring to its lightness or darkness in relation to its body colour. For example, if you’re looking for a fancy yellow diamond you will come across stones in our collection described as vivid yellow, fancy intense yellow, or fancy yellow. These adjectives are all GIA grading terms used to describe a gem’s hue, tone and saturation. The same terms are used to grade pink, blue, green, black, red, purple and orange diamonds.

Grading fancy color diamonds is a complex process. But as general rule, the more rich and saturated the color, the higher the value.