Magnificent Jewels
Our Sotheby’s Magnificent Jewels Pre-Auction Analysis focuses on elements that are not always visible to the untrained eye. We discuss characteristics such as Inner-Grade, Color Dispersion, and Undertone – collectively termed IDU. Professionals use the IDU method intuitively when analyzing a Fancy Color Diamond. The acronym we use makes these elements easier to remember.
Members who read this analysis should see it as a valuable supplement to the GIA report. A detailed explanation of the FCRF’s grading methodology can be found at the end of this article. We recommend reviewing it closely to broaden one’s professional vocabulary for describing fancy color diamonds to clients.
Please note that we analyze and grade diamonds under LED lights and relative to their grade on the GIA report.
The Grades
We use grades 1, 2, 3, and 4, with 1 being the lowest grade. Grade “4+” is granted in rare cases and denotes diamonds with exceptional characteristics. diamonds that receive a minimum total IDU score of 9 without a red remark pass the industry premium threshold and can be traded easily. Fancy Color Diamonds that are graded 10 or above (without a quality remark) are usually sought after by high-end jewelers and collectors.
For your convenience, we have added direct links to diamonds’ GIA reports and FCRF rarity stats.
- All images in this analysis were taken with an iPhone 13 Pro; no filters were applied.
- All auction valuations are per-carat and listed in US Dollars.
- The FCRF evaluates chosen diamonds during each auction based on expert judgments.
Disclaimer
This analysis reflects the opinions of the FCRF professional team. It does not constitute a recommendation to buy or not buy a particular diamond. Buyers assume the responsibility of verifying any information with the auction house. At times, mistakes can happen in the visual analysis and report placement. Therefore, one should not rely solely on this analysis for buying purposes.
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Lot: 28
Description: 40.72 ct, Fancy Brown-Orange, Radiant, SI1.
Analysis: A remarkably large orange diamond featuring approximately a 40% brown modifier in its hue. This diamond exhibits exceptional visual qualities, characterized by a strong orange color sensation. According to the FCRF “True Face-Up” tool, this radiant cut appears ~10% larger, a key attribute valued by jewelry buyers.
High Auction Estimation: $17,191 pc
Price realized: $685,800 Total
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12
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Lot: 55
Description: 3.63 ct, Fancy Vivid Yellow, Marquise, VS2.
Analysis: A 3.63-carat vivid yellow marquise diamond from the mid-20th century. Its odd proportions and open culet testify to the era in which it was polished. The GIA report indicates that the inclusions are external, suggesting potential for clarity improvement. Apart from a few colorless patches, the diamond displays exceptionally high visual qualities.
High Auction Estimation: $55,096 pc
Price realized: Didn’t reach the minimum
Visual Assets:
Inner Grade..……………….4
Color Dispersion.….……3
Undertone..…………………4
Total Visual Score….11 out of 12
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Lot: 60
Description: 133.03 ct, Fancy Vivid Yellow, Cushion, VS2.
Analysis: An exceptionally large, vivid yellow cushion-shaped diamond. Its prominent and tall crown, coupled with the concentration of most of its color under the table area, could suggest that this diamond was recut from an old-mine cut diamond. The intensity of its color is on the lower end, bordering on the intense grade.
High Auction Estimation: $37,586 pc
Price realized: $36,083 pc
Visual Assets:
Inner Grade..……………….1
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….6 out of 12
Quality Remark: low inner-grade and dispersion
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Lot: 77
Description: 7.37 ct, Fancy Intense Orangy Pink, Emerald, VS1.
Analysis: An intense orangy-pink emerald-cut diamond. The diamond exhibits a pleasant color sensation, consistent with the color description provided in the report. The color is evenly dispersed across the four corners of the pavilion, leading to a low characteristic color dispersion for an emerald cut. In this instance, the internal graining is noticeable and contributes to the crystal’s reduced translucency. The combination of an orange modifier and the substantial internal graining may indicate that the diamond is a type IIa.
High Auction Estimation: $271,370 pc
Price realized: $229,782 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.….……3
Undertone..…………………3
Total Visual Score….9 out of 12
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Lot: 84
Description: 3.68 ct, Fancy Gray-Violet, Old European-cut, SI1.
Analysis: An Old-Mine Violet diamond with a gray modifier, originating from the early part of the previous century. Violet diamonds are among the rarest in the fancy color category, especially those exceeding one carat. This diamond exhibits low color dispersion, typical of round diamonds. However, the presence of gray significantly dominates the overall color sensation.
High Auction Estimation: $217,391 pc
Price realized: $1,143,000 Total
Visual Assets:
Inner Grade..……………….3
Color Dispersion.….……2
Undertone..…………………2
Total Visual Score….7 out of 12
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Lot: 87
Description: 1.2 ct, Fancy Vivid Orange, Oval, I2.
Analysis: An elongated, vivid orange, oval-shaped diamond with I2 clarity, characterized by two large feathers extending along its shape. The diamond exhibits a bright color sensation, enhanced by its yellow fluorescence. In most cases, yellow fluorescence tends to impact the brightness of an orange diamond more positively than orange fluorescence.
High Auction Estimation: $183,333 pc
Price realized: $254,000 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.….……3
Undertone..…………………4
Total Visual Score….11 out of 12
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Lot: 91
Description: Ring with 4.53 ct, Fancy Green, Cushion, I1; 1.04 ct, Fancy Grayish Pink-Purple, Radiant, I2 and 1.03 ct, Fancy Purplish Pink, Radiant, I2.
1.04 ct: GIA
Analysis: A Fancy Green cushion diamond, described by the GIA as ‘Partially faceted‘, likely due to the substantial unpolished areas around the girdle. These areas are preserved to maintain the thin green layer at the diamond’s outer ‘skin’. Removing this layer would eliminate its color. The closed ring setting in which it was mounted plays a crucial role in concealing the naturals and enhancing the diamond’s color. The combination of the unpolished areas and strong blue fluorescence results in an opaque color sensation.
- The two highly included pink side diamonds were challenging to analyze due to the gold mounting.
High Auction Estimation: $150,000 total
Price realized: Didn’t reach the minimum
Visual Assets (4.53 ct):
Inner Grade..……………….2
Color Dispersion.….……2
Undertone..…………………2
Total Visual Score….6 out of 12
Quality Remark: a significant amount of natural/strong blue
Visual Assets (1.04 ct):
Inner Grade..……………….3
Color Dispersion.….……2
Undertone..…………………2
Total Visual Score….7 out of 12
Visual Assets (1.03 ct):
Inner Grade..……………….3
Color Dispersion.….……2
Undertone..…………………2
Total Visual Score….7 out of 12
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Lot: 94
Description: 10.89 ct, Fancy Intense Yellow, Radiant, VVSI.
Analysis: A 10.89-carat radiant cut fancy intense yellow diamond, featuring a low inner-grade and noticeable colorless patches on the crown. Utilizing our ‘Face-Up’ tool, the diamond presents the appearance of a 12.81 – 13.08 carat diamond, appearing ~19% larger compared to diamonds of similar weight.
High Auction Estimation: $22,957 pc
Price realized: $17,494 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion.….……3
Undertone..…………………3
Total Visual Score….8 out of 12
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Lot: 106
Description: 15.11 ct, Fancy Intense Yellow, Cushion, VSI.
Analysis: Upon close examination of the facet alignment, it becomes evident that the diamond was repolished from its original Old-Mine cushion cut to enhance its saturation. When an old cut diamond is subjected to such a procedure with minimal weight loss, it typically exhibits low color dispersion, as shown here.
High Auction Estimation: $33,091 pc
Price realized: Didn’t reach the minimum.
Visual Assets:
Inner Grade..……………….2
Color Dispersion.….……1
Undertone..…………………3
Total Visual Score….6 out of 12
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General
We use 1, 2, 3, 4, and 4+ to grade the three visual elements that GIA is silent about, although they impact the value dramatically.
Inner grade refers to the strength of color within each GIA saturation category:
Grade 1 weakest, bordering the saturation below.
Grade 2 weak (most common).
Grade 3 full-bodied color (above average).
Grade 4 very strong saturation.
Grade 4+ applies to the vivid category only, exhibiting the strongest possible saturation (rarely seen).
Undertone refers to a subtle hue influence in the body color of the diamond.
For example:
A Fancy Blue Diamond with a significant gray presence in its general appearance will be graded with a low undertone grade of 1. A Fancy Blue that has no gray influence that is close to a primary blue will receive the grade, 4.
In a Pink Fancy Color Diamond, a diamond with a warm undertone (such as orange or brown) will receive a low undertone grade. A pink diamond with a cold undertone (such as purple) will receive a high grade.
In Yellow Fancy Color Diamonds, a low foreign influence or a light orange influence will grant the diamond a high undertone grade. When the yellow undertone looks like a true primary yellow, it will receive the rare grade 4+. Green and brown undertones will grant a low grade in the yellow category.
Color Dispersion relates to how well the color is dispersed in the face-up view of a Fancy Color Diamond, regardless as to whether the GIA grades the diamond as even. A diamond with many colorless areas will receive the grade 1, while a diamond that exhibits its face-up view with no colorless patches will receive the grade 4+. Unlike the first two elements, the color dispersion is not a gemological quality and is the result of cutter proficiency.
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