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Fancy Colour Diamonds


While fancy colour diamonds have traditionally been a small part of the diamond business, their popularity and availability have grown in the past several decades. In the 1980s the Argyle mine in Australia began marketing its brown stones under trade names like “Champagne” and “Cognac.” Argyle reached its goal of making the public more aware of fancy colour diamonds and dropped its marketing campaign in the late 1990s.

Other most well-known historical and current sources of fancy colour diamonds are India, South Africa, and Australia. Other diamond mine locations, including Brazil, Venezuela, Guyana, and Indonesia, also produce fancy colour diamonds.

Natural Fancy Colour Diamonds

Natural fancy colour diamonds are formed in the earth under immense pressure and heat, and their colour is a result of natural processes. The colour can be caused by a very small number of defects or impurities (about one per million of lattice atoms). Yellow and brown diamonds are very common in nature; however, almost all colours are represented in diamonds. Coloured diamonds get their hues like blue, yellow, green, purple, pink, orange, or red due to tiny amounts of impurities, such as nitrogen, boron, hydrogen, or radiation exposure. These impurities cause the diamond to absorb certain wavelengths of light and reflect others, resulting in the unique colour and making these naturally occurring diamonds incredibly rare and valuable. However, you can get also get coloured diamonds that been treated to achieve these colours.

Fancy colour diamonds value will increase as the intensity and purity of the colour shows. Large, vivid fancy colour diamonds are exceptionally rare and extremely valuable. Nevertheless, some fancy diamond colours can be more muted than pure and strong.


Treated Fancy Colour Diamonds

Besides naturally coloured diamonds, we have create various processes of treating diamonds to create fancy coloured diamonds. Treated fancy coloured diamonds are diamonds that have undergone a treatment to enhance their colour. These treatments may include irradiation, coating, and HPHT (high pressure, high temperature) treatments. The treatments are used to create fancy colours such as yellow, blue, green and pink.

There are a variety of colours that diamonds can have. The Irradiated diamonds that are yellow, orange, green, blue and pink shades are free of residual radioactivity. After irradiation, the resulting fancy colour is steady and will not fade.

Black coloured treated diamonds are obtained by a graphitization process.

The High Pressure, High Temperature (HPHT) processed diamonds, no irradiation, generate colours, such as pink, blue, and a large range of yellow, lime, orange and brown hues, and produce colours that are unlikely to fade.

Fancy Colour Diamond Grading

When it comes to grading fancy-coloured diamonds, the Gemological Institute of America (GIA) established a standard for grading coloured diamonds, which is now widely recognized and accepted as the global standard.

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 (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.

The 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 big impact on value.

Although colour is the primary value factor, clarity still. However, inclusions that pose a threat to a diamond's durability can significantly reduce its value. Even if such diamonds have a low clarity grade due to numerous inclusions, they 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.
Calico - GIA Colour Diamond Clarity Scale

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 can influence colour. Particularly mixed fancy cuts such as the radiant, have been found to intensify certain colours, such as 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.

Calico - GIA Fancy Blue Colour Diamond - Fancy Cuts

Like conventional white diamonds, the rarity and value of fancy colour diamonds also depend on their size. Fancy 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.
Calico - GIA Colour Diamond Carat Scale

The Differences Between Natural Fancy Coloured Diamonds Vs Treated Fancy Coloured Diamonds?

The main difference between natural and treated fancy coloured diamonds is the origin of their colour. Natural fancy colour diamonds are formed in the earth's crust over millions of years, while treated fancy colour diamonds are created by subjecting natural diamonds to high pressure and temperature or irradiation to enhance their colour. Coloured diamonds can be created from lab diamonds, but those will be noted on the diamond certificate. There are however, pros and con’s to choosing each.

Pro’s & Con of Colour Enhanced Diamonds


Affordable: Treated fancy colour diamonds are generally much less expensive than naturally occurring fancy colour diamonds. Treated diamonds can be a great option for people who want the look of a fancy colour diamond but have a limited budget.

More Colour Options: With treated fancy colour diamonds, you have access to a wider range of colours than you might with natural fancy colour diamonds. This is because diamond treatment techniques can enhance or change the colour of the diamond, giving you more options to choose from.

Customization: Diamond treatments can be customized to achieve specific colours or effects. This means that buyers can work with a jeweller to create a unique and personalized diamond that meets their exact preferences and specifications. This level of customization may be difficult or impossible to achieve with natural fancy colour diamonds.


Durability: Natural fancy colour diamonds are more durable and retain their colour better over time, while treated fancy colour diamonds may lose their colour or become discoloured. Therefore, treated fancy colour diamonds are also more likely to be damaged by heat, chemicals, and other environmental factors thus requiring more maintenance and require more careful handling.

Value: Treated fancy colour diamonds will generally have a lower value compared to natural fancy colour diamonds. This is mainly due to the fact the naturally occurring colour diamonds unique origin, extreme rarity, and durability. In the diamond market, natural fancy colour diamonds command higher prices and are considered more desirable.

Rarity: Treated fancy colour diamonds are less rare than natural fancy colour diamonds, which may be a drawback for some buyers. Some people may prefer the exclusivity and rarity of a natural fancy colour diamond, even if it comes at a higher cost.