Naturally Colored Diamonds
Diamonds colored naturally are very rare and fetch very high prices. There are three ways in which colored diamonds are formed by nature.
The first method is when a foreign element is introduced into the raw carbon material that will become a diamond. For example, nitrogen can cause a diamond to have yellow or orange hues while boron can turn it blue.
The second method is when pressure compresses the carbon and creates a red, pink or purple hue.
Lastly, natural radiation deep in the earth generates diamonds with colors of green or blue. Green, red and purple diamonds are considered very rare and command high prices.
Indeed, there are only six naturally formed red diamonds currently in the market. One can only imagine the prices these stones will fetch.
Natural fancy colored diamonds are so rare that there exist at least 10,000 colorless stones for each one of them.
Inclusions, regarded as undesirable in a colorless stone, often contribute unique tones and interesting flashes of color in a fancy color diamond.
Within a given grade, the clarity, color distribution and cut affect the final price of the stone. Smaller diamonds (less than 0.80) carat are considerably less expensive than the rarer large gems.
Exceptionally well cut stones and stones with a VVS or IF clarity however have a price tag comparative to the quality . Secondary colors, such as brownish yellow, reduce cost.
Although white diamonds are cut in a standard way to maximize light refraction, colored diamonds are viewed differently by the cutter who usually considers the stone’s inclusions.
These can enhance the diamond’s color and with the facets and angles also giving added color to a diamond, the cutter must consider what shape would best bring out the gemstone’s color.
A good cut gives a fancy diamond its sparkle and helps to bring out the most intense color possible.
The best prices are offered by “direct from the mine” wholesalers, merchants who buy either rough stone or newly cut diamonds directly from the source. Not all wholesalers will sell to private buyers, but the ones who do can save their clients a considerable sum of money.
Several factors influence the price of colored diamonds. The rarer and more intense the color, the more the diamond will cost.
Unlike white diamonds, the presence or absence of inclusions is of secondary consideration. Colored diamonds have a grading all their own, and are categorized by the GIA into 9 different groups : Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep and Fancy Vivid.
Yellow and brownish diamonds are the most common; blue, green and especially red are the rarest and most valuable. Yellow and pink diamonds are the most commonly purchased, though fashion change and they may well dip in popularity in the future. Celebrity tastes greatly influence trends in the area of luxury products.
Mined mainly in Africa and South America, yellow diamonds are classified in order of price and rarity, beginning with fancy light, fancy yellow, then fancy intense and finally, vivid – the rarest of them all.
The rarity of fancy yellow diamonds – only 2 percent to 3 percent of diamonds mined in the world are considered “fancy yellow” – makes them popular among women who want to make a statement with their stones.
An extremely pale yellow diamond will be classified somewhere in the X to Z color range, making it closer to a low end white diamond rather than a fancy color. Yellow diamonds of a high intensity, such as vivid or deep, are quite rare.
But yellow diamonds can easily lose their luster with improper cutting and polishing. Whereas it would take a skilled diamond cutter two days to cut a 2-carat brilliant white diamond, a similar fancy yellow diamond would take two weeks to cut.
Knowing how to distinguish a quality yellow diamond is important when making a purchase. Make sure the diamond is certified. The certificate should say “natural.” Otherwise the diamond has been treated to look yellow.
Look for an intensity of color. The certificate should also say “even.” This guarantees an evenness of color throughout the stone and is evidence of a higher quality diamond.
Choose complementary settings; 18-karat yellow gold is best for enhancing the natural intensity of the yellow diamond.
The Argyle mine, a leader in the production of brownish diamonds which were previously unwanted by consumers, was the first to introduce the terms ‘champagne’ and ‘cognac’ as a marketing campaign to encourage appreciation of these stones. It seems to have worked, and brown diamonds are becoming more expensive as they are being incorporated more frequently into jewelry.
Champagne diamonds are less expensive than white diamonds but Champagne diamonds with a secondary pink color are extremely popular. When faced up, these stones display light to bold flashes of pink in their fire. These stones are available in a sparkling range of champagne tones, from light champagne to fancy cognac.
Natural fancy pink diamonds are rare, and account for only a fraction of one percent of the output of the Australian Argyle mine. Pink diamonds mined in India, Brazil and Africa are usually lighter in color than the intensely pink Argyle diamonds. These diamonds are primarily divided into five color categories: Pink, Purplish pink, Brownish pink, Orange pink and Pink Champagne. Pink diamonds without any secondary coloring are the rarest and most expensive of all.
By volume, the Argyle mine in the Kimberley region of Western Australia is the largest diamond supplier in the world. It is also world’s foremost source of intensely colored pink diamonds, producing 95% of the world supply. However, only an extremely small proportion of Argyle diamonds production is Pink color, in fact less than one tenth of 1 percent.
The fame of Argyle’s pink diamonds has grown over the past decade. At the 1989 Christie’s auction in New York a 3.14 carat Argyle pink sold for $1,510,000. Privately, Argyle has sold pink diamonds for up to $1 million a carat.
Synthetic or Treated Fancy Colored Diamonds.
Fancy color diamonds are becoming increasingly popular, so gemologists have developed ways to create affordable versions by using heat and radiation to turn brownish and yellow diamonds into colorful show-stoppers, at an affordable price. Fancy colored diamonds can also be man-made in labs. There are a variety of methods used to color diamonds.
One man-made method to produce fancy colored diamonds involves irradiating a natural diamond that possesses an unattractive color. Irradiation is a process in which a diamond is exposed to a source of radiation that changes the position of atoms within the stone thus causing its color to change.
Irradiation, followed by high heat treatment, is used to convert brown and yellow diamonds into fancy colors such as green, vivid yellows, blues, purples, reds and other colors. This color change is usually permanent, but could possibly be affected if high heat is used during setting repairs.
Treated or synthetic diamonds may look very appealing to the consumer because of the price and uniformity of color; however, these diamonds have no value to the serious buyer and have little resale value. Therefore, if you are purchasing a colored diamond for investment it is vital to obtain certification from the diamond seller. The certificate should come from a reputable laboratory and contain the origin of the stone and the natural origin of the stone’s color.
If there are questions as to a stone’s origins, a lab certificate should be obtained to verify its authenticity. If a colored diamond is offered at a bargain price, it is safe to assume the color is synthetic.
High Pressure High Temperature Treatment (HPHT) was first used to turn low-priced yellowish diamonds into fancy colored gemstones, but it is also used to transform them into completely colorless diamonds that can be sold for a much higher price. Some companies claim HPHT isn’t an artificial treatment at all, calling it a technique that finishes the job nature started. Certainly diamonds are exposed to such an environment in the earth, and when that process is repeated in a man-made environment it is difficult to detect by examination of the stone alone. This process uses pressures of over 55,000 atmospheres and 1400C, plus molten iron to convert graphite to diamond.
GIA grading reports now indicate when HTPT treatments are detected by stating “HPHT Annealed” or “Artificially Irradiated” in the Origins portion of a report. The FTC requires that any diamonds subjected to HPHT be labelled as such.
The secret to making diamonds was discovered in the 1950s, when diamonds were synthesized almost simultaneously by Swedish and American researchers.
Currently approximately 80 tons of synthetic diamonds are produced annually – mostly for industrial use.