Yellow diamonds are the most common of the fancy color diamonds and are probably the best known by the public. Nitrogen is responsible for the color, present in trace amounts in the crystal lattice of the diamond. Many diamonds are weakly tinted with yellow, but when graded past the "Z" grade on the GIA diamond color grading scale, the color is saturated enough to qualify for the fancy color grading scale, which is as follows: fancy light, fancy, fancy intense, fancy dark, fancy deep and fancy vivid. Yellow diamonds that don't reach the "fancy" grade but still have a pronounced yellow body color are cleverly utilized by today's savvy jewelry designers to create spectacular designs. Some yellow diamonds can have a modifying color which can be orange, green or brown. The fancy yellow diamond color range reflects different strengths of color and a wide range of tones; consumers can pick and choose what works for them. Yellow diamonds occur most commonly in Africa, where many historic stones have been found, including the cushion-shape 128.51-carat "Tiffany" diamond, and the 10.73-carat "Eureka" diamond, the first diamond to have been recognized as authentic in Africa at the beginning of the diamond rush there.
Characterization and Grading of Natural-Color Yellow Diamonds
To better understand the yellow diamonds currently in the marketplace, as well as identify possible changes in their trends seen over a five-year period, researchers at the GIA Gem Laboratory analyzed gemological data collected on more than 24,000 natural-color yellow diamonds examined in the calendar years 1998 and 2003. These data included color grade, type of cut, clarity grade, weight, ultraviolet fluorescence, and UV-visible and infrared spectra. Among natural-color colored diamonds, those with a yellow hue are some of the most abundant; even so, they are much less common than the colorless to light yellow diamonds associated with GIA's D-to-Z color grading scale. Since the yellow color is a continuation of the gradation of color associated with the D-to-Z scale, there can be misconceptions about the color grading, which involves different procedures from those used for D-to-Z grading. The grading and appearance aspects, as well as other characteristics of yellow diamonds, are discussed to clarify these differences. The authors have also identified five subgroups of type I yellow diamonds, which (with some overlap) are characterized by representative spectra and color appearances.
19ct and 20ct Yellow Round Diamond
Color Grading "D-to-Z" Diamonds at the GIA Laboratory
Since its introduction in the early 1950s, GIA's D-to-Z scale has been used to color grade the overwhelming majority of colorless to light yellow gem-quality polished diamonds on which laboratory reports have been issued. While the use of these letter designations for diamond color grades is now virtually universal in the gem and jewelry industry, the use of GIA color grading standards and procedures is not. This article discusses the history and ongoing development of this grading system, and explains how the GIA Laboratory applies it. Important aspects of this system include a specific color grading methodology for judging the absence of color in diamonds, a standard illumination and viewing environment, and the use of color reference diamonds ("master stones") for the visual comparison of color.
Yellow diamonds, behind brown diamonds are the most abundant of the fancy colored diamonds. Achieving their color from the concentration of nitrogen in the atomic structure these stones can achieve extremely high degrees of saturation.
GIA awards the highest grades to diamonds with both high saturation and a low amount of tone. The term "canary" has been adopted by the trade as well as the public to describe a yellow diamond and "Zimey" to describe the strongest of vivid yellows.
Yellow can be modified by the hues brown, orange and green. Brown is considered a great deterrent to the value of the stone with orange and green sometimes considered an advantage. Still strait yellows especially in strong saturation grades are rare and valued highly.
Yellow differs from other colors in that their exists a wide range of color in the highest GIA grade, vivid yellow.