Photo curtesy of GIA
Diamonds come in many colours, most are colourless to just ‘off white’ or tinted. But when the colour is strong enough to be attractive and desirable we call it a "fancy coloured diamond” or FCD.
Colourless D to Z tinted diamonds are colour graded through the side in the face-down position. But FCD’s are graded by Labs from the face-up.
Fancy Colour Terminology on Grading Reports:
Fancy yellow diamond grades issued by labs start at Fancy Light, Fancy, Fancy Intense, Fancy Dark, Fancy Deep, Fancy Vivid. Very rare colours in diamonds (like pink, blue and green) can receive these 3 lower grades: Faint, Very Light and Light - because there is a market for them and they fetch high prices.
The diamond on the far left below is ‘Fancy Light Yellow’ (FLY). The diamond on the far right is a ‘Fancy Vivid Yellow’ (FVY) yellow. The two centre diamonds are both ‘Fancy Intense Yellow’, or ‘FIY’ which is the broadest range. FIY prices vary accordingly just like the range of D to I in colourless diamonds; 50% price variations are common. Comparison shopping for FCD’s is hard unless you have some comparative sample. Comparisons from online photos are impossible.
Diamond colour graders at the Gemological Institute of America (or GIA) have the tough job of making grade the calls - they evaluate each diamond for hue, tone, and saturation in controlled lighting boxes like that used to judge fabric colours. They are rarely considered to be consistent, but they are the best there is in an imperfect world. You must use three descriptors to describe colours.
The Munsell colour wheel shows how Hue, Tone and Saturation work together.
Hue Around the ‘equator’ - a diamond's overall body colour e.g. orangish yellow, yellow, greenish yellow
Tone Through the ‘centre of the earth’ - A diamond's lightness or darkness
Saturation The intensity or saturation of colour
Secondary or modifying colours impact the hue and value of fancy colour.
A yellow diamond with a green secondary hue is graded as "Fancy Greenish Yellow." A blue diamond may have a grey secondary colour, and will be graded as "Fancy Greyish Blue". Secondary colours in yellow diamonds include greenish yellow (more expensive), brownish yellow (less expensive), and orangish yellow (can be more expensive – pure orange is very rare).
Extinction or Dark Zones
At Holloway Diamonds we reject most FCD’s on the market because they have ugly dark zones as a result of bad cutting. All these photo’s are from GIA or diamonds for sale on the Internet and GIA graded them as having as ‘Even’ colour, which it is obvious they are not. Sadly most FCD’s have dark zones that are persistent ugly patches.
The science of cutting FCD’s is a very different to cutting colourless diamonds where contrast from dark zones is what makes them sparkly and brilliant – the alternating bright dark bright flashes as you rock a white diamond. If a diamond has a dark zone in a photo then it probably will in real life too, and light leakage zones always appear dark once the diamond is set.
Fluorescence and Complementary Colours
Colours directly opposite each other on the colour wheel are said to be ‘complementary colours’.
Blue and yellow are complementary colours; red and cyan are complementary; and so are green and magenta.
Mixing together two complementary colours of light gives you white. So adding blue fluorescence can make a yellow diamond paler. Yellow diamonds that fluoresce yellow will be a stronger yellow in daylight which has more UV light. Unfortunately, many yellow diamonds actually fluoresce blue and one of the things we do is ensure that our diamonds do not lose too much colour if they are fluorescent.
The 4Cs of Fancy Coloured Diamonds
Coloured diamonds, or fancy coloured diamonds (FCDs), are valued differently from colourless diamonds, although the same four grading terms apply: Carat, Clarity, Colour and Cut.
Carat weight has a similar impact on pricing as for colourless diamonds. However, top coloured rare pink, blue, purple and orange diamonds above one carat (1.00ct) attract a premium, reflecting their rarity in larger sizes. Fancy yellow diamonds, which are often found in very large rough crystals, attract a smaller premium in larger sizes.
Clarity refers to the size, placement and visibility of inclusions. Consumers use terms like flaws, which implies the diamond can break. Sadly this is more likely to be true in the case of pink diamonds. Many people are unaware that diamonds can and do break. Argyle pink diamonds often have large surface reaching ‘feathers’ (a polite word for cracks) reducing durability.
However, clarity has less impact on price with Fancy Coloured Diamonds than it does with colourless diamonds. Inclusions in coloured diamonds are also harder to see.
The owner who submits a FCD can request a ‘partial cert’ from the GIA, which does not mention the clarity grade. Buyers usually take this to mean the stone has a clarity of I1 or lower. In some cases the owner may include an I1 grade because they think some buyers would argue the diamond is an I2. There are many plus $1 million FCD’s with grades as low as I2!
Argyle pink diamonds made such a big impact on the world of pink diamonds because they often have such striking colour. Bubble Gum, Fairy Floss or Baby Pink are terms used for the most desirable colours. See the round diamond below:
The colour in the centre is of this stone is ‘bubble gum pink’ - the most desirable from a demand and resale point of view. However this Vivid Pink is not as expensive as a Fancy Red graded colour.
The big difference in colour and appearance between the central table region and the outer crown facets is because of bad cutting. The stone has a very shallow pavilion and an extremely steep crown angle and would be unsaleable if it was a colourless (D to Z) diamond. This stopped me from considering buying this diamond. The original cutter sent me a 3D file of the diamond as I considered recutting it, but the estimated 30% weight loss would drop it under the magic 1.00ct weight.
The Hope diamond at 45.52ct on display in the Smithsonian Institute in Washington DC. It is one of the worlds most famous coloured diamonds.
The GIA colour descriptor on every FCD GIA cert.
Colour accuracy from photos
Interpreting how diamonds really look from a photo, even if the same vendor took them, is tricky. Images from different vendors makes it impossible. In this example the first three photos may be consistent because the same set up has been used from the same vendor (though the background variances could mean they were photoshop’ed). The pear shape is dulled by inclusions. The fourth image is less flattering but probably more realistic. It’s from a manufacturer from whom I buy hundreds of diamonds a year, and I know their photos match their stones.
A fourth factor is modifying secondary colours mentioned above. Both Argyle and GIA have crazy unpredictable variances in their grades which are evident when you see the diamonds side by side, as shown in the example below.
GIA gave both these pink diamonds the same grade - FIPP (Fancy Intense Purplish Pink)
What Causes Colour in Diamond?
Diamond is pure carbon crystallised under immense heat and pressure more than 100km beneath the earth's surface. The and have been shot to the surface within an hour or two in a volcano. They are ‘snap frozen’ - if the journey takes too long they revert back to graphite or carbon gases. Sometimes other atoms are trapped in a diamond as it grows or during its violent ride to the surface. Nitrogen is the most common; the tiniest amount causes blue light to be absorbed giving the diamond a yellowish colour. Australia Argyle diamonds are an exception, they are very pure and the cause of the rare pink colour is a freak of nature. Unfortunately the cause of colour is stress that means most are heavily included.
Natural blue diamonds are not ‘sapphire blue’, they are more of a light greyish blue shade, more "steely". The most famous blue is The Hope diamond in Washington's Smithsonian Institute. It has a horrid history and is considered cursed. Horrible deaths befell many of its owners; guillotining during the French Revolution, to a Wall Street broker jumping to his death in 1930. A lead mould from the ‘French Blue’ was scanned by Scott Sucher using my Cut group associates advanced rough diamond planning technology to prove the stone was recut from the earlier versions. Jeweller Harry Winston owned it briefly to donate to the Smithsonian. His insurance company and armed couriers were discussing the cost and method of delivering the priceless gem from New York to Washington. While they were in discussions Harry strolled down to the post office and posted the diamond by ordinary mail in a cigarette packet! He did call the museum curator first thing the next day and suggest he be present at the mailing room.
Dresden Green 41Carats
Green diamonds have come in contact with radioactive minerals such as uranium. As Marie Curie discovered, radiation stains the outside of a diamond. Cutters must be careful not to cut away too much of the outer green "skin". Authenticating that the radiation occurred naturally requires laboratory analysis. Often the cutter submits the stone in the rough to GIA during the cutting process so the lab can authenticate the natural origin as it is not always possible to determine if the radiation is natural or done recently to cheat.
The Argyle diamond mine does not produce yellow diamonds. All its diamonds are in a brown, not yellow series. We use the terms champagne and cognac to describe their colour. They are a less expensive alternative FCD. The Ellendale mine was discovered about the same time as Argyle, and is relatively not that far away. It has been opened and operating for the past decade and it has produced many fine fancy yellow diamonds
A little known and relatively rare FCD are white opalescent diamonds. These are collector's oddities and we have a small selection at Holloway Diamonds. They are a lot less expensive than transparent colourless diamonds, and we think they were a real collector’s bargain. Gems and Gemmology, the GIA’s journal has written papers about white diamonds. Who knows, they may become the next fashion thing like black diamonds.
Pave' set Black diamonds are popular in high-fashion jewellery. We have made collections of black and white diamond designs that have been very popular. They are often used in men's jewellery. Most of the black diamond fashion jewellery is made with small irradiated and or heat treated natural diamonds. Most large black diamonds are low clarity diamonds and when heated the inclusions go black. Natural untreated black diamonds have been heated in the earth and are indistinguishable from stones that have been heated by man. Good surface lustre of heat treated blacks is rare. They can also be relatively fragile.
Treated and synthetic coloured diamonds
General Electric was equal first to make synthetic diamonds for industrial abrasives in 1955. In the 1990’s GE's R&D team discovered a way to improve the colour of some rare large diamonds (type II) using an advanced high pressure / high temperature treatment (HPHT). The whitened gems more than doubled in value and can be bought today as Belataire™ diamonds. The gem industry requires gem dealers to disclose any treatments on invoices and GE and an American partner company were embroiled in some controversy because they felt disclosure was unnecessary. Within months gemmologists discovered tests to identify HPHT diamonds.
This has been a story repeated throughout gem history. A new way to cheat is developed and shortly after a detection method is discovered and the cheats are caught.
One unfortunate cheating practice that is rife at present are companies who claim to turn deceased ashes into synthetic or man-made lab grown diamonds. I believe this is a fraud and the perpetrators are simply buying synthetic diamonds and reselling them as if they were actually composed or human or pets remains.