Diamonds come in a variety of colours, but the vast majority of diamonds sold in the jewellery industry range from near colourless to very light yellow or brown. The most valuable are colourless diamonds (which have extraordinary ability to absorb all rays of light equally) and natural fancy coloured diamonds (due to their rarity and uniqueness). The colour in Natural Fancy coloured Diamonds is due to the presence of certain “foreign” elements like nitrogen, boron, etc. which were introduced by nature during the diamonds formation deep in the earth.
In order to classify diamonds as NATURAL, they are tested and certified in a Gemmological laboratory such as GIA, HRD, or AGS . Once a stone has been certified, it has its own unique and personal ID which includes an ID number, measurements, weight, shape, clarity, polish, symmetry and fluorescence.
The price of fancy coloured diamonds is still effected by the 4Cs, but coloured diamonds are polished in a different manner than white diamonds in order to emphasise the colour as much as possible. Natural Fancy Coloured diamonds can appear as one primary colour, without any secondary hue – for example, fancy blue diamonds, fancy pink diamonds, etc. When it appears as a single colour, the price of the diamond will be considerably more expensive than a diamond with a secondary hue – for example, fancy Orange Pink, or fancy Greyish Blue.
The intensity grading system is unlike white diamonds, which range from the letter D-Z. Natural Fancy coloured diamonds are graded as either Light, Fancy Light, Fancy, Fancy Intense, Fancy Deep , Fancy Dark, and Fancy Vivid. The stronger the colour, the higher the price!
Each coloured diamond is different not only because of its natural body colour but also because of the way it is shaped and finally polished. Most fancy colour diamonds are cut into cushion or radiant shapes forms, which best bring out the depth of hue. The most skilled cutters shorten the optical light path through the diamond, creating the bright sparkle that is reflected from them. Cutting deeper pavilions and creating different facets may intensify colour.
The cutting of coloured diamonds is significantly important, performed by highly skilled craftsmen who combine their technical knowledge with a deep appreciation for beauty and colour. Different regions of the earth have yielded particular types of coloured diamonds, and each colour requires a master cutter’s knowledge and appreciation to unlock the beauty within.
Colour is the most important factor in determining the beauty and value of a gemstone. There are four main factors involved in a gemstone’s colour: hue, tone, saturation, and distribution.
is the term used for the actual colour of the spectrum: red, orange, yellow, green, blue, indigo or violet. The more pure a gemstone’s hue, the more valuable it is. Because gemstones are composed of many naturally occurring elements, they typically emit one dominant colour and one or more underlying colours.
represents how light or dark a stone appears depending on how much brown, black, gray or white is present.
is the intensity of brightness of the colour. The more colour saturated a gemstone is, the more valuable it becomes.
is how evenly the colour spreads out across the body of the gemstone.
No other jewel combines the rarity, beauty and sex appeal of natural fancy coloured diamonds. The majority of white diamonds are not rare! For over 60 years the DeBeers cartel has convinced Americans that diamonds equate with love and are to be treasured. However, natural fancy coloured diamonds are truly exceedingly rare and are simply geological flukes. For every 100,000 D-flawless diamonds, there is probably one coloured diamond, and it is probably not flawless. The beauty and the rarity of these coloured diamonds have spawned unprecedented desire and unparalleled prices.Red diamonds are undoubtedly the rarest of coloured diamonds. Green and Blue coloured diamonds follow closely behind and are exceptionally rare. Following in rarity are the Purple, Pink and Violet colours. The next layer of rarity goes to orange and olive. Yellow, brown, champagne, gray and black diamonds are only modestly rare.
“For every 100,000 D-flawless diamonds, there is probably one coloured diamond”
Before the discovery of the Argyle mine in Western Australia in the mid-1980s, the finest quality pink diamonds found elsewhere were very faintly coloured. Argyle pinks and purple-pinks in contrast, have a characteristic full-bodied, bright and intense colour. “Of every 39.2 million carats of diamonds mined at the Argyle, only 40 carats of pink diamond is deemed worthy of being presented for sale at their annual, invitation-only tenders. This is rarity as defined by Mother Nature.Some of the rarest and most famous coloured diamonds were brought together at the Smithsonian Museum in 2003, being part of an exhibit titled The Splendour of Diamonds (above photo). The exhibit lasted from June 27th to September 30th and featured a number of exceptional coloured diamonds: (top row left to right) the Steinmetz Pink, the Millennium Star, the Allnatt Diamond (bottom row left to right) the Heart of Eternity, the Pumpkin Diamond, the Tiffany Yellow, the Moussaieff Red and the Ocean Dream.
Fancy coloured diamonds are graded according the saturation of the colour along with different hues present in them. Following is a sample scale of colour saturation: In Fancy coloured diamonds, main dominant colour is listed after the modifying colours. If a diamond is graded as Fancy Grayish Greenish Yellow then the dominant colour would be yellow with gray and green as modifying colours.One important factor to remember is that in coloured diamonds, clarity is secondary to the intensity of the diamond’s colour.
Due to the rarity and high prices of naturally occurring coloured diamonds, people were forced into finding a lower priced alternative. Scientist came up with a process which mimics the way diamonds are coloured naturally. The most common process used in enhancing diamonds in the industry is called irradiation. This is a process in which natural diamonds with non fancy colours are subjected to high energy particles (alpha, beta, gamma, neutrons, x-rays or microwaves) in a properly equipped laboratory. Some of these diamonds are often subjected to further colour enhancement by heating them at high temperatures of up to 1400 degree Celsius. The diamonds processed in this manner are called enhanced fancy coloured diamonds and are completely safe to the wearer. Most diamond colours can be artificially induced. Proof that a stone has a natural colour can only be obtained from a gemological laboratory. When considering the purchase of an expensive stone, it is important to have a certificate from an independent laboratory stating the natural origin of its colour. However, problems can occur: for instance, when testing green diamonds, it is difficult to differentiate a natural from an artificially-induced colour. The process of artificially altering the colour to green involves irradiating which can also occur naturally. Thus green stones, despite their rarity, are more difficult to sell unless indisputable proof of colour origin can be found