Deconstructing a sundrop
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The Sun Drop Diamond (click to enlarge)


The Analysis (Click to enlarge)

  Deconstructing a sundrop

by the Gemewizard team
April 15, 2012


This past week, the Sotheby's auction house announced the upcoming auction of a fancy vivid yellow, 23.02 carat cushion-shaped step-cut diamond. The diamond, which at pre-auction is valued at $65,161 to $86,881 per carat, will be offered for bidding at Sotheby's 'Magnificent Jewels' auction in New York next week.

The announcement brought to mind another fancy vivid yellow that recently was sold at auction, the 110.3-carat pear-shaped 'Sun-Drop' diamond, which was sold last November at Sotheby's in Geneva for the world record amount for a yellow diamond of just over $10.9 million. We decided to pay the deserved tribute to the Sun-Drop and dedicate this month's color analysis article to it.

Yet how do we go about doing it? It is not as if we had the diamond in hand and were able to take images of it at will, under different lighting conditions. In any case, the 'Sun Drop' diamond had already been already certified with a "fancy vivid yellow" color grade, the highest and most desirable color for a yellow diamond. So what other information could we add?

After much deliberation, we concluded that we could analyze one of the most common images of the gem, shown against a black background (Figure 1) - a challenging image for the analyzer, and verify whether the image would maintain the fancy vivid yellow grade.

As expected, the analysis of this diamond in the image was quite complicated, as its color is produced by a large amount of different shades of yellow reflections, with the black background contributing to the color frenzy. However, as it turned out, the average resultant color of fancy vivid yellow, was obtained without a challenge for the analyzer. Therefore, we decided to inspect the color components, including lighter and darker reflections from inner facets, and their relative occurrence within its fancy vivid grade.

First, we took the image of the diamond and set the sampler to eliminate the black background. Next, we tuned it for an in-depth scan to check all pixels in the image one-by-one and collect the yellow brilliancy- and scintillation-reflected areas. Then, we excluded facets displaying the black reflections of the background. The collected samples were aggregated into several major color groups and placed in a color pie chart, representing the color components of the average resultant color.

From reviewing the collected data (Figure 2), we found that almost half (49.54%) of the color of the diamond was a pure fancy vivid yellow, a significant and dominating amount. Another 45% was contributed by darker tones of fancy deep brownish yellow (23.85%) and fancy dark yellow (22.02%). The last 4.95% represents lighter colors, which slightly reduced the darkening effect.

Our analysis of the Sun-Drop image clearly confirmed diamond's fancy vivid yellow color grade. The 50% fancy vivid yellow, as the dominant color, is the main factor influencing the overall vivid yellow color and the key for the purity and the intensity of the color grade, while the fancy deep and fancy dark moderators, give the diamond its magnificent rich and deep appearance. The overall results create a special color.

Undoubtedly the Sun Drop is exceptional and considering its size, it is definitely a suitable gem for holding a world record price, at least until further notice.

If you have a magnificent gemstone or colored diamond and would like Gemewizard® to analyze it in one of its next Gem Color Reports, please contact us at info@gemewizard.com.