When is a diamond a ‘fancy color’ ?
A stone is called a fancy color diamond if it has enough color for it to be considered an acceptable or saleable color in its own right and can be defined as a specific color – which may differ slightly depending on the color tint. This distinction may change with time and market-related fashions.
The colors of fancy color diamonds are graded by viewing the stones face-up, in the direction a client would view the stones in their jewellery. In contrast, near-colorless diamonds are laboratory graded by viewing side-on, in order to avoid the brilliance and fire that would mask their subtle variations in tint. To grade any colour consistently, we need a consistent light source. As with many other industries that rely on accurate assessment of color, the diamond industry uses a standard light source. This is used in gemmological laboratories worldwide and has a colour temperature of about 5000–5500 begin_of_the_skype_highlighting 5000–5500 end_of_the_skype_highlighting K, close to that of daylight. Stones must also be graded loose – unset (in jewellery) – because reflections from their settings would influence their color grade if viewed within an item of jewellery.
Once a stone has been described or graded as fancy, the strength of color seen is then considered, for example :
> faint
> very light **
> fancy light
> fancy
> fancy intense
> fancy vivid
** These are fairly weak colors and this term is usually only used when referring to blue or pink diamonds, reflecting their extreme rarity and great value.
Terms such as deep and dark may also be used to help the descriptive process. Then the basic hue is described. For example ‘brownish yellow’ would describe a stone with a primary hue of yellow together with a secondary brownish hue.
Diamonds are also assessed for their clarity. This means free from inclusions and/or small internal features such as tiny mineral grains in the diamond. The fewer and smaller the inclusions in the stone, the higher the value of the stone. Logically, larger stones command much higher prices however, it is the color that most strongly influences the value when dealing with this spectacular group of stones and this is particularly true for the more intense colors.
The Value of Rare Diamonds
The most valuable fancy colors are red, blue and pink; a good quality red or blue diamond is extremely rare. An exceptional example of this rarity is the Blue Hope diamond. This is a 45.52 carat cushion-shaped stone, that can now be seen in the Smithsonian Institution in Washington, DC, USA.
Pink stones are also rare. In 1981, the Argyle Mine in Northwest Australia was opened. This became a good source for pink stones albeit a limited source in its capacity. Pink diamonds have also been found in Africa and South America. In 1947, in Tanzania, the famous Williamson diamond was discovered. This stone is a round, brilliant cut pink diamond of 23.60 carats. Today, it is owned by The Queen.
The most common cause of color in blue diamonds is a trace amount of boron. In red and pink diamonds, the color is believed to be caused by imperfections in the crystal lattice.
Interesting enough, the Argyle Mine in Australia also produces large quantities of brown diamond, one of the least expensive fancy stones. As with pink and red colors diamonds, the cause of the brown color is due to imperfections in the crystal lattice.
Unlike most other fancy colors, the value of brown diamonds tends to diminish with stronger colour. With the quantity of fancy colors being mined at Argyle, an extensive marketing campaign was introduced for both pink and brown diamonds. Who would want a brown diamond? Argyle Mine introduced the terms ‘champagne’ and ‘cognac’ as color descriptions, thereby increasing the profile of fancy color diamonds worldwide and encouraging designer jewellers to consider using fancy colors in their designs.
One of the more frequent and popular fancy colors is yellow. Fancy yellow stones come from many different locations, including Africa, Australia and South America. They vary in intensity from off-white to deep yellow. The cause of color in these stones is due to trace amounts of nitrogen.
Green diamonds, although rare, can also be found naturally. Famous examples of these colors are the Tiffany, a cushion-shaped, strong yellow colored diamond weighing an impressive 128.51 carats. It is owned by the Tiffany Company in New York. The Dresden Green is a 40.70 carat pear-shaped green diamond, on display in Dresden, Germany.
Black diamonds and Chameleons
A slightly unusual type of fancy color diamonds is the black diamond. These stones are difficult to polish, as one of the causes of the blackness in these stones is the minute inclusions throughout the stone, rather than a trace element or imperfection in its crystal structure. These stones tend to go in and out of fashion and, unlike most of the other fancy color diamonds which are transparent, these stones are usually opaque, yet they still display the wonderful ‘adamantine’ lustre almost unique to a diamond.
Another very rare group of color diamond is the ‘Chameleon’ diamonds. These stones actually have the ability to change color under different lighting conditions, or upon heating. Most Chameleon diamonds have a greenish–greyish–yellow colour. When they are first displayed after being stored in the dark they may appear yellow, changing to green over a period of time. This alteration can often be reversed by heating the stone or returning it to darkness for several hours or days.
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