Magnificent Jewels & Noble Jewels
Our Sotheby’s Magnificent Jewels & Noble 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 stones with exceptional characteristics. Stones 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.
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: 511
Description: 3.03 ct, Fancy Intense Yellow, Pear, VS1.
Analysis: A 3.03 fancy intense yellow with a large colorless area in the center resulting in a low color dispersion. No green or brown undertone is visible in the hue exhibiting an absolute yellow color.
High Auction Estimation: $11,828 pc
Realized price: $13,046 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.……….2
Undertone..…………………4
Total Visual Score….9 out of 12
Quality Remark: low color dispersion
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Lot: 512
Description: 4.83 ct, Fancy Vivid Yellow, Cushion, VVS2.
Analysis: A fancy vivid yellow cushion shape diamond with a warm undertone and a colorless crown. According to the diamond diary, the face-up view of this diamond appears ~3% smaller relative to its carat weight.
High Auction Estimation: $32,464 pc
Realized price: $23,384 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….8 out of 12
Quality Remark: Warm undertone, appears ~3% smaller.
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Lot: 514
Description: 3.19 ct, Fancy Light Purplish Pink, Pear, VS2.
Analysis: A 3.19 carat fancy light purplish pink with a low inner-grade and a large colorless bowtie in the center of its face-up.
High Auction Estimation: $94,796 pc
Realized price: $97,363 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….7 out of 12
Quality Remark: low dispersion and inner-grade – strong blue fluorescence.
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Lot: 515
Description: 1.18 ct, Fancy Intense Blue, Round, VVS2.
Description: 0.94 ct, Fancy Deep Blue, Round, I1.
Analysis: two round, blue fancy color diamonds that feature different color grades: Intense and Deep. They also show a significant and visible difference in the size of their table facets—55% versus 69%. Each diamond exhibits a strong inner-grade and a pleasant hue with minimal gray undertone. The I1 clarity on the 0.94 carat results from two large and eye visible feathers on the table.
High Auction Estimation: $338,114 pc
Realized price: $499,443 pc
Visual Assets (1.18 ct),
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
Visual Assets (0.94 ct):
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12
Quality Remark: low compatibility, I1 is visible to the naked eye.
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Lot: 525
Description: 4.51 ct, Fancy Vivid Yellow, Heart, SI1.
Analysis: A 4.51-carat heart-shaped diamond featuring a vivid yellow hue with a solid inner-grade and lacks a prominent green or brown undertone. The large, colorless crown restricts the color to the table area. The presence of an indented natural on the face-up view may prevent the diamond from being sold in the high-end market. According to the diamond Diary the face-up of this 4.51 corresponds to a 6.02 – 6.23 carat
High Auction Estimation: $34,767 pc
Realized price: $31,303 pc.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: low color dispersion
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Lot: 530
Description: 2.46 ct, Fancy Pink-Purple, Pear, SI1.
Analysis: A 2.46-carat purple pear-shaped diamond with approximately a 40% pink color modifier displays a large, colorless bowtie in the center of the stone. The SI1 clarity is due to a prominent black crystal located under the table but does not appear on the GIA plot. Several chips are found on the stone.
High Auction Estimation: $122,927 pc
Realized price: $114,777 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………4
Total Visual Score….9 out of 12
Quality Remark: low color dispersion
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Lot: 588
Description: 5.43 ct, Fancy Vivid Yellow, Pear, SI1.
Analysis: A 5.43-carat vivid yellow pear-shaped diamond, featuring a wide rounded area, has a colorless bowtie at its center, which results in low color dispersion. Buyers should note that the accompanying GIA report is dated 2011.
High Auction Estimation: $94,880 pc
Realized price: $176,795 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: low color dispersion
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Lot: 604
Description: 103.62 ct, Fancy Intense Yellow, Cushion, VS2.
Analysis:A very large Fancy Intense Yellow cushion-shaped diamond. This important stone is described in its GIA report as having faint fluorescence; however, upon placing it under UV light, it seems as if the grade does not reflect reality. Based on the photograph provided, you may assess the fluorescence grade for yourself. Additionally, when examining the diamond with a 10x loupe, we observed that the crystal of the diamond is not very clear and imparts an “oily” sensation. The VS clarity is based on a prominent black inclusion situated under the table.
High Auction Estimation: $39,236 pc
Realized price: $24,009 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
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Lot: 614
Description: 5.78 ct, Fancy Pink, Emerald, VS1.
Analysis: A rectangular emerald-cut diamond. The stone displays a pink hue, mainly through its corner pavilion facets, resulting in an X-shaped pattern. The pink hue is pleasant and inner-grade is moderate. According to the Diary, the face-up view is ~26% larger compared to the average for its carat weight
High Auction Estimation: $263, 529 pc
Realized price: Didn’t reach the minimum.
Visual Assets:
Inner Grade..……………….2
Color Dispersion.…….…1
Undertone..…………………3
Total Visual Score….6 out of 12
Quality Remark: Low dispersion
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Lot: 621
Description: 4.42 ct, Fancy Intense Green, Radiant, VS2.
Analysis: A relatively large Fancy Intense Green Radiant cut diamond with a bright and pleasant hue. The colorless frame on the crown is prominent, confining the color under the table facet. Although the fluorescent is Strong Blue it has no effect on the brilliance of the diamond.
After a careful examination, we have detected a dark coating on the gold cup beneath the pavilion of the diamond, which may affect the inner grade. Buyers should take this into account.
High Auction Estimation: $529,593 pc
Realized price: $410,696 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
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Lot: 624
Description: 31.6 ct, Fancy Vivid Yellow, Radiant, VVS2.
Analysis: A large square vivid yellow radiant-cut diamond, featuring a solid inner grade without any significant green or brown undertones in the hue. From the face-up view, a prominent colorless pattern is visible due to inefficient facet alignment on the pavilion, resulting in low color dispersion.
High Auction Estimation: $64,506 pc
Realized price: $42,443 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
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Lot: 642
Description: 8.08 ct, Fancy Vivid Yellow, Emerald, VS2.
Analysis: A Fancy Vivid Yellow Emerald-cut diamond with a very high inner-grade with no brown or green undertones in the hue. The facet alignment is classic, with minimal modification, resulting in typical color dispersion with large areas that present a low color. Upon examining the diamond with a 10x loupe, it is possible to see a brown cloud under the table.
High Auction Estimation: $56,832 pc
Realized price: $82,120 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12
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Lot: 644
Description: 3.46 ct, Fancy Deep Blue, Cushion, VS1.
Analysis: An elongated, Fancy Deep Blue cushion-shaped diamond. The facet alignment is not coherent relative to the shape, resulting in the Fair symmetry. It is reasonable to assume that the decision to adopt an old-cut style was made to reduce color retention in an attempt to achieve the vivid grade.
High Auction Estimation: $529,249 pc
Realized price: $456,616 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
Quality Remark: Fair Symmetry
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Lot: 645
Description: 12.62 ct, Fancy Orangy Pink, Emerald, VS1.
Analysis: A large Fancy Pink emerald-cut diamond, featuring approximately 20% orange hue in the mix. The undertone aligns with our expectations from the color description in the report, a trait not commonly found in diamonds with this combination of colors
High Auction Estimation: $128,685 pc
Realized price: Didn’t reach the minimum.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.…….3
Undertone..…………………3
Total Visual Score….9 out of 12
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Lot: 649
Description: 4.76 ct, Fancy Intense Orangy Pink, Oval, VS2.
Analysis: A 4.76-carat Fancy Intense Orangy Pink oval, featuring a strong inner grade and a pleasant color sensation and a black crystal resaulting the VS clarity. However, please approach this particular analysis with reservation, as the diamond is completely covered with gold at the bottom, which may affect its visual aspects. The GIA report is dated 2013.
High Auction Estimation: $320,000 pc
Realized price: $266,929 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 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 stone.
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 stone with a warm undertone (such as orange or brown) will receive a low undertone grade. A pink stone with a cold undertone (such as purple) will receive a high grade.
In Yellow Fancy Color Diamonds, low foreign influence or a light orange influence will grant the stone 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 stone as even. A stone with many colorless areas will receive the grade 1 , while a stone 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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