Natural fancy yellow diamonds are extraordinarily rare, exclusive and expensive.
They belong to an exclusive group of extremely rare natural colored diamonds occurring in nature in myriad colors.
The usual perception is that a diamond is a colorless (or white) stone. In fact most diamonds are indeed colorless. Nevertheless, a tiny percentage of these gemstones acquire particular shades of colors. This depends upon certain sets of atmospheric conditions existing in the vicinity of the diamonds during their formative years.
How does a yellow diamond become yellow?
A diamond is a crystallized isotope of carbon. The majority of natural diamonds develop in high pressure & high temperature conditions. Such conditions exist at extreme depths of 140 to 190 kms inside the Earth’s Mantle. Carbon or carbon containing minerals provide the seed carbon source. The metamorphic crystallization of the carbon into a diamond happens over a period of hundreds of millions of years. This is nothing short of a miracle.
Purer carbon seed & near perfect crystalline lattice structure yield clearer & colorless diamonds. Yet, the conditions in which a diamond develops are far removed from the ideal and sanitized conditions of a laboratory.
At times the crystalline structure of the diamond gets distorted by the immense pressure at those depths. At other times, the seed carbons source gets impregnated with impurities like nitrogen, boron or hydrogen. Many a times such factors occur simultaneously.
Depending on the type of impurity (or crystalline distortion), the resulting diamond absorbs certain spectrums of light and reflects others. We perceive the color of the diamond based on the reflected spectrum of light.
The most common impurity element found is nitrogen. Nitrogen atoms have an unequal number of electrons than carbon. When both of them bond, one of the nitrogen electrons remains unattached. These free electrons in orbit around the nuclei partially absorb blue & violet light wavelengths. The wavelengths which are not absorbed appear yellow to the human eye thus giving the diamond its yellow coloration. Nitrogen impurities impart the yellow color to a diamond.
Overall, natural colored diamonds are extremely rare. However, among the elite group of natural colored diamonds, yellow diamonds are the most common. Among the 100 largest diamonds in the world, one third of them are yellow. The most famous being The Kimberley Octahedron, weighing massive 616 carats.
Natural fancy yellow diamonds should not be confused with the transparent (or white) diamonds of inferior quality. They too, happen to appear pale yellow on account of presence of trace nitrogen impurities. The color grades of white (transparent) diamonds range from D to Z. Grade D diamonds are the whitest/clearest and most valuable, while grade Z are tinted with faint sickly yellow to brown and are least valuable in comparison.
A diamond with stronger yellow going beyond the Z color grade confers the coveted fancy yellow grade upon the diamond. Such a diamond is highly sought after by the celebrities, the royalties, the fashion forward, and the jewelry designers. The diamond becomes pretty expensive and goes beyond the reach of most of us.
As the diamonds become progressively darker yellow in color, they are given their own separate color grades like fancy light yellow, fancy yellow, fancy intense yellow and fancy vivid 求婚戒指價錢 yellow (also known as canary yellow).
Like all natural colored diamonds, the deeper and more intense the yellow in a yellow diamond the higher the value of the diamond will be. A tiny.25-carat yellow diamond can be priced as high as 10,000 dollars depending on its clarity and cut. Larger 6 carat Fancy Vivid Yellow diamonds have been sold for as high as $57.000 per carat.
All yellow diamonds look more intense once set in yellow gold.
Similar to white diamonds, namely color, cut, clarity and carat are the factors that need to be considered before choosing a yellow diamond. With Colored Diamonds, Clarity is not as important as Saturation of Color and their prices depend on saturation of color. A diamond must be certified by a gemological laboratory to be called natural.
Radiant and cushion cut work well with large, yellow diamonds because of their predisposition to hold color well. Using one of the round cuts has been known to lower the intensity of color by a full grade in certain cases.
The Argyle mine in Western Australia is the most prolific producer of yellow diamonds followed by diamond mines in South America and South Africa. Around one in every 1000 diamonds mined is a fancy colored diamond.