Colour Diamond Grading
Fancy Colour Diamond Grading
The GIA colour grading system for coloured diamonds uses a combination of hue, tone, and saturation to determine a diamond's colour grade. Hue refers to the diamond's dominant colour, tone refers to how light or dark the colour is, and saturation refers to the intensity or purity of the colour.
The GIA colour grading scale for coloured diamonds ranges from "Faint" to "Fancy Deep" and includes 10 different colour grades. The highest grade is "Fancy Vivid," which is reserved for diamonds with the most intense and purest colours.
The GIA also evaluates other factors when grading coloured diamonds, such as clarity, cut, and carat weight, which are taken into consideration when determining the overall value of a coloured diamond.
Colour
Colour (Hue, Saturation, and Tone) is the main determinate of value for a fancy-coloured diamond, although, the other members of the 4 C’s (carat, clarity, and cut) will still have a distinct impact that value and these other factors can also impact the depth of colour that shows in a stone.
The contemporary grading system for coloured diamonds relies on three primary colour characteristics: hue, tone, and saturation. Hue identifies the dominant colour of the diamond, tone gauges the lightness or darkness of the colour, and saturation determines the colour's intensity. Gemologists employ this grading system to determine the value and rarity of the coloured diamonds, which can exhibit strikingly vivid or subdued pastel hues.
Coloured Diamonds are given a grading of one of the following: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid, Fancy Dark, and Fancy Deep. Fancy Intense and Fancy Vivid diamonds usually have the highest value.
There are certain colours that are rarer in nature and consequently more valuable. The rarest and most valuable colours are saturated pinks, blues, and greens. In all cases, even very slight colour differences can have a significant impact on value.
Although colour is the primary value factor, clarity has influence in their value. Inclusions that pose a threat to a diamond's durability can significantly reduce its value. Even diamonds with a low clarity grade, due to numerous inclusions, can still be highly valued by experts if their face-up colour is appealing. Additionally, fancy colour diamonds may display colour graining, which is considered an inclusion.
There are two aspects that can influence a diamond's colour: size and shape. The larger the size and weight of a diamond, or the deeper its pavilion, the more it allows light to travel further into it, resulting in more intense and enriched colour.
Additionally, certain styles of cuts, particularly mixed fancy cuts such as the radiant, have been found to intensify yellow colour in lower grade diamonds. Skilled cutters can transform these stones into fancy yellows through careful fashioning. This enhances the perceived colour and thus increases the value of the diamond per carat. Moreover, the radiant style provides a higher yield from the rough compared to a standard round brilliant.
Like conventional white diamonds, the rarity and value of fancy colour diamonds also depend on their size. Fancy natural colour diamonds are exceptionally rare to begin with, therefore, the larger the size of the coloured diamonds the more valuable they are. Especially those diamonds categorized into the fancy vivid colour, this will drastically increase the value as their size increase due to the incredible rarity.
