Among the precious gems provided by planet Earth, yellow diamonds stand out for their brilliance and incomparable beauty. Plus, it’s one of the most common diamonds, popular for its sublime brilliance and unprepossessing prices.
The yellow diamond crystal discovered in Yakutia (Siberia), by the Anabara Company, a subsidiary of ALROSA. In the image you can see this jewel, whose weight is 34 carats.
Does the yellow color detract from the diamond?
A classification of diamonds, based on a color scale, where the absence of color confers a greater value to the gem, carried out by the Gemological Institute of America, (acronym in English GIA), catalogs diamonds by color from D to Z Where “D” is the highest grade for colorless diamonds.
The yellow undertone does not always detract from the diamond. The existence of these gems is splendid, as long as the color is strong and obvious, when viewed “face up”.
The following image shows the “Large Yellow Diamond Crystal”, it has a slightly intense yellow hue that does not classify as an “elegant color” diamond.
Under the “Z” grade of the GIA classification, there is a small group of diamonds with a strong yellow hue, attractive when viewed “face up”. These extravagant stones belong to a unique scale, based on the intensity and quality of the yellow hue. GIA classifies them as Fancy Light, Fancy, Fancy Intense, Fancy Dark, Fancy Deep, or Fancy Vivid.
Pure yellow and transformed yellow diamond
The yellow diamonds most desired have a pure yellow color. Although such purity is extremely rare, the yellow diamonds most show traces of flop. Being yellow-green and yellow-orange the two most common color transformations.
Color-modified diamonds are less costly, with characteristics similar in size and color to a pure yellow gem. The following image corresponds to a GIA classification, namely the Fancy Vivid Orangy Yellow.
Role of nitrogen in yellow diamonds
The pure nature of a diamond is composed of carbon atoms, united by covalent bonds in a crystalline network, colorless, without inclusions or alterations.
Just one nitrogen atom per 100,000 carbon atoms can be enough to impart a yellow color to diamond, however the way in which nitrogen is introduced into the crystal lattice is also important.
Nitrogen gives diamonds their yellow hue. This can replace carbon atoms in the crystal lattice of diamond, due to its small size. When it occurs the crystal will selectively absorb blue light, and transmit yellow light. When incident on the stone, the human eye will see a yellow diamond.
Nitrogen can exist in the diamond lattice in several ways:
- “Centre C” : a nitrogen atom bonded to four carbon tetrahedrons (as seen in the image). The ratio of one nitrogen atom per 100,000 carbon atoms causes a perceptible yellow color in the crystal. This replacement is effective on artificial diamonds, not natural diamonds.
- “A-Nitrogen Center” : replacement with nitrogen pair (as seen in the image). This replacement has little impact on the color of the diamond.
- “N3 defect” : This nitrogen modification generates a strong yellow color in natural diamonds. Three nitrogen atoms clustered around an empty carbon position in the crystal lattice. As seen in the following illustration. This alteration is almost always accompanied by an “N2 alteration”, generating a yellow coloration evident to the naked eye.
“Layers” and “Canaries”
The yellow diamonds They have received various names, the most common being “Capas” and “Canarios”. Diamonds born in the Cape Province (South Africa) at the end of the 19th century were called “Cape”. Later, the diamond merchants called them “Capas” influenced by their origin.
Currently, jewelers around the world call “Cabo” yellow diamonds pale without specific origin. They call diamonds with an indisputable yellow color “Canaries”, very luxurious.
Adjustments between design and color
The harmony of colors is essential, contrasting them so that the color of the gem stands out, or the color of the metal is in accordance with the diamond. Gold, platinum, can give a unique appearance to the jewel.
Consideration should be given to reflections from the metal band and tip, which will contribute to the appearance of the diamond. Reflected light and the color of the base metal will have a considerable impact on light colored diamonds.
The most famous yellow diamonds
The Tiffany Yellow Diamond
In the Cape Province (South Africa) is the Kimberley Mine, where the largest yellow diamond was unearthed in 1878, whose gross weight was 287.42 carats. Later it was acquired by Charles Tiffany.
It underwent modifications to improve its virtues, obtaining an extremely brilliant yellow diamond. The design became known as the “Brilliant Cut Modified Antigua Cushion”.
The image corresponds to a Tiffany yellow diamond
Yellow diamond “The Incomparable”
A glamorous faceted brownish yellow diamond weighing 407 carats. The unique triangle cut called “Triolet”. Here are four reasons that make this beautiful gem “incomparable” with any other diamond:
- It is the largest diamond in the world flawless internally.
- Its discovery in the 1980s where a kid got the 890 carat rough in a pile of reject minerals.
- In 1988 it became the largest diamond ever sold publicly.
- In 2002 it was offered on eBay making it the largest diamond ever offered in an online auction.
Yellow Diamond Treatments
It is possible to alter brown diamonds to create yellow diamonds. Treatments such as high temperature, high pressure, irradiation, annealing and coating have served to obtain the yellow hue.
When a treated diamond is sold, the condition and what treatment was performed must be reported. Some opt for this type of diamond, due to its lower cost and qualities similar to natural diamonds.
Yellow diamonds created in laboratories
The first attempts to generate diamonds artificially resulted in diamonds with a yellow color. Due to the wide availability of nitrogen in the environment, and a low concentration of this element, it can impregnate a diamond with a yellow color.
Currently there is greater control over the fair amounts for the production of diamonds artificially. These have more affordable prices for those who love jewelry.
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