15th December 2017 Guides
When it comes to buying diamonds, usually a clear colourless sparkler comes to mind but have you considered a coloured diamond? Diamonds can come in a wide variety of colours and create a unique jewellery piece. Here is a beginner’s guide to coloured diamonds:
In diamonds, rarity equals value. With diamonds in the normal range, value is based on the absence of color, because colorless diamonds are the rarest. However, with coloured diamonds (also known as fancy diamonds) — the rarest and most valuable colors are saturated pinks, blues, and greens. Red, green, and blue diamonds with medium to dark tones and moderate saturations are extremely rare and can fetch large prices. In all cases though, even very slight color differences can have a big impact on value. Diamonds with a noticeable hint of any hue, even in light tones and weak saturation, as long as they show color in the face-up position, qualify as fancy colors. The most common fancy diamonds, but nonetheless beautiful, are yellow and browns.
With the advancement of technology in all sectors of the diamond industry, some companies have developed and perfected tools and processes to artificially alter the color of a diamond. There are strict guidelines for reporting these stones, as their value is drastically lower than their natural colored counterparts. There are three primary methods to artificially alter the color of a diamond: irradiation with high-energy sub-atomic particles, application of thin films or coatings, and the combined application of high pressure and high temperature (HPHT).
The first two methods can only modify color. They are often used to turn cape colored diamonds into fancy yellows. HPHT, however, actually alters the internal color of the stone and can be applied to either rough or polished diamonds. HPHT is often used to transform rare Type IIa brown diamonds into white stones. In recent years, advancement in the lab-grown diamond community has led to the production of lab-grown diamonds for all fancy color ranges including blue and pink. While no treatment is illegal, there are strong regulations for the disclosure of such. Attempting to sell treated stones as natural is considered fraud. However, as a precaution make sure to be aware and deal with a reputable company to avoid being misled.
Grading fancy color diamonds is complex and specialized, and it takes highly trained laboratory graders to complete the process accurately. Depending on several factors such as saturation, the position of colour and the colour itself will affect the grade and value. Fancy color diamonds are graded on a nine-point scale with color saturation descriptors: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep, Fancy Vivid. The difference in value between one level of saturation and the next can range between 50-100 %. Fancy color diamond grading is further complicated because such stones often simultaneously exhibit a component shade of different colors. As with all grading, make sure it’s from a reputable grading lab.
Even the cut of fancy color stones is different compared to a colourless diamond. Ultimately, light refraction and perfect proportions, even inclusions, are less important than color. As a result, it is uncommon to see fancy color stones produced as round brilliants, which is the most coveted cut for most colorless stones. Non-round shapes, such as pears, radiants, emeralds and cushions are more common fancy color shapes as they tend to bring out stronger color shades. Size also plays a part, the larger a diamond is, or the deeper its pavilion, the farther light can travel in it. This can often lead to a richer, more intense color.
If you need more information on any of these aspects, please don’t hesitate to get in touch with one of our expert staff by phone or by using the form below. We also have another beginner’s guide to the Four C’s, Cut, Clarity, Colour, and Carat which can be found here.
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