Magnificent Jewels
Pre-Auction Analysis: December 7th, 2022, Sotheby’s New York, Magnificent Jewels
Our Sotheby’s New York 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: 10
Description: 3.69 ct, Fancy Gray-Blue, Cushion, SI2
High Auction Estimation: $216,802 pc
Price realized: $273,171 pc
GIA Report: View
Analysis:
A 3.69 carat Old Mine Cushion-style diamond with a ~40% Gray modifier and ~60% blue as the body color. In absolute terms, color dispersion in this diamond is low. However, stones with a periodical facet alignment are often assessed in a more forgiving manner.
The gray undertone dominates the face-up view and doesn’t meet our expectations from the color description on the report.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score…. 8 out of 12
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Lot: 12
Description: 3.71 ct, Fancy Pink, Cushion, VS2
High Auction Estimation: $404,312 pc
Price realized: $161,321 pc
Rarity: 3-6 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 3.71 Fancy Pink Cushion-cut diamond with a colorless crown and a very prominent brown color sensation. Consequently, a very warm pink will appear as a strong Inner-Grade. The surface area of the face-up is large relative to the stone’s weight. The GIA report is dated 2013.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………1
Total Visual Score….7 out of 12
Quality Remark: Brown undertone.
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Lot: 29
Description: 10.67 ct, Fancy Gray, Emerald, SI1
High Auction Estimation: $187,441 pc
Price realized: $103,918 pc
GIA Report: View
Analysis:
This 10.67 carat, Fancy Gray Rectangular Emerald-cut diamond is quite rare, especially in this size. The undertone of a gray diamond is graded by examining the amount of green or brown sensation in the color from the face-up view. In this case, the amount is insignificant.
The amount of graining, on the other hand, is significant and creates fogginess in some parts of the diamond.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
Quality Remark: Heavy graining.
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Lot: 43
Description: 5.46 ct, Fancy Vivid Yellow, Oval, VVS2
High Auction Estimation: $50,366 pc
Price realized: $50,770 pc
Rarity: 2-5 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 5.46 carat Fancy Vivid Yellow Oval-cut diamond with a 1 x 1.23 ratio. The surface area of the face-up is a bit small relative to its weight. The Inner-Grade is very high, exhibiting an attractive yellow color with no undertone. Colorless areas are visible around the crown.
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12
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Lot: 54
Description: 2.08 ct, Fancy Intense Blue, Cushion, VS2
High Auction Estimation: $ 721,153 pc
Didn’t reach the minimum
Rarity: Once every 5-6 years – Share this rarity result – Here
GIA Report: View
Analysis:
A 2.08 carat Fancy Intense Blue Rounded Cushion. The colorless areas on the crown are prominent and the Inner-Grade is weak. The face-up of the stone is large relative to its weight.
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
Quality Remark: low inner-Grade.
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Lot: 55
Description: 3.24 ct, Fancy Vivid Blue, Cushion, IF
High Auction Estimation: $ 2,469,135 pc
Withdrawn from auction
Rarity: Once every 5-6 years – Share this rarity result – Here
GIA Report: View
Analysis:
A 3.24 carat Fancy Vivid Blue Cushion-cut diamond with several colorless patches on the crown. The Inner-Grade is strong and the amount of gray undertone is insignificant.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
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Lot: 63
Description: 14.28 ct, Fancy Intense Yellow, Emerald, VVS1
High Auction Estimation: $26,260 pc
Price realized: $25,589 pc
Rarity: 1-2 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 14.28 carat, Square Emerald-cut diamond with a low Inner-Grade. Color dispersion is high for a step-cut and there is an insignificant amount of undertone in the color. The diamond has several external inclusions on its crown that could probably be removed in a simple re-cut. The GIA report is dated 2014.
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: Low inner-grade. 72% depth.
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Lot: 76
Description: 303.10 ct, Fancy Deep Brownish-Yellow, Pear, IF
High Auction Estimation: $65,984 pc
Price realized: $40,875 pc
GIA Report: View
Analysis:
An extremely large Fancy Deep Brownish-yellow diamond with a famous story about its accidental discovery. The stone appears in professional literature. It was exhibited in different museums and received wide public recognition. These details are mentioned because they may add value for certain collectors.
The shape of this 303.10 carat is defined as a modified Pear shape. The immensely large facets result in large light prisms: red, blue, and yellow flashes that create a special visual effect and improve the diamond’s overall color sensation. These large, colorful flashes are not seen to such an extent in regular-sized diamonds.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
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Lot: 97
Description: 4.35 ct, Fancy Orangy Pink, Pear, IF
Description: 3.46 ct, Fancy Orangy Pink, Pear, VS2
High Auction Estimation: $160,919 pc
Price realized: $125,839 pc
GIA Report 2175972148: View
GIA Report 2175972138: View
Analysis:
Two Pear-shaped diamonds in different weight categories with different dimensions and an inconsistent outline. Both diamonds have a pleasant undertone, not having the typical warm (brown) color sensation. The 4.35 carat has a strong Inner-Grade, while the 3.46 exhibits a low one. Both diamonds have a pleasant overall appearance but are too different to ever be considered a matching pair.
Visual Assets 4.35 ct:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….10 out of 12
Visual Assets 3.46 ct:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….9 out of 12
Quality Remark: Low compatibility.
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Lot: 103
Description: 2.05 ct, Fancy Vivid Yellow, Round, VS1
High Auction Estimation: $34,146 pc
Price realized: $27,659 pc
Rarity: 6-12 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 2.05 Fancy Vivid Yellow Round Brilliant-cut diamond with a green undertone. The angles on the crown create a dark reflection on the face-up view. The saturated color combined with the green color sensation indicates that the diamond most likely originated from the Zimmi area of Sierra Leone.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………2
Total Visual Score….7 out of 12
Quality Remark: Low undertone.
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Lot: 104
Description: 3.01 ct, Fancy Deep Yellow-Green, Cushion, SI1
High Auction Estimation: $26,578 pc
Price realized: $18,838 pc
GIA Report: View
Analysis:
A 3.01 Fancy Deep Yellow-Green Cushion-cut diamond with no colorless patches on the face-up and no brown or gray undertone present in the hue. The strong Inner-Grade is inherent in most diamonds with a deep color grade.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………4
Undertone..…………………3
Total Visual Score….10 out of 12
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Lot: 106
Description: 3.24 ct, Fancy Vivid Yellowish Orange, Pear, I1
High Auction Estimation: $46,296 pc
Price realized: $105,000 pc
GIA Report: View
Analysis:
A 3.24 Fancy Vivid Yellowish-Orange Pear shape with a high Inner-Grade and color dispersion. The glow of yellow fluorescence creates a pleasant color sensation. The I1 clarity is a result of many inclusions situated under the table.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………4
Undertone..…………………4
Total Visual Score….11 out of 12
Quality Remark: I1 Clarity.
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Lot: 107
Description: 2.01 ct, Fancy Blue, Round, IF
High Auction Estimation: $348,258 pc
Price realized: $313,433 pc
Rarity: Once every 5-6 years – Share this rarity result – Here
GIA Report: View
Analysis:
A Round modified Fancy Blue diamond with a low dispersion and Inner-Grade. The modification on the diamond’s pavilion is the result of a re-polish procedure performed on what used to be a classic Round Brilliant diamond, probably with a lower saturation. No gray undertone is present in the hue.
*GIA report dated 2008
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………4
Total Visual Score….8 out of 12
Quality Remark: Low color dispersion.
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Lot: 154
Description: 30.29 ct, Fancy Yellow, Round, VVS2
High Auction Estimation: $19,808 pc
Price realized: $28,703 pc
Rarity: Once every 8-12 years – Share this rarity result – Here
GIA Report: View
Analysis:
A large Round Brilliant Fancy Yellow diamond with low color dispersion, a typical feature for this shape. The 66% table and small open culet are clear indicators that the diamond was manufactured in the middle of the last century, when these diamonds were sold without a GIA report nor referred to as Fancy Color Diamonds.
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….7 out of 12
Quality Remark: Low dispersion.
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Lot: 161
Description: 31.20 ct, Fancy Intense Yellow, Radiant, VS1
High Auction Estimation: $25,641 pc
Price realized: $29,077 pc
Rarity: 1-3 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A Rectangular Fancy Intense Yellow Radiant-cut with many colorless parts under the table, a typical appearance for rectangular diamonds with a small crown and low depth percentage (61.3%). The Inner-Grade is low, and no undertone is visible in the hue.
The surface area of the face-up is large relative to the stone’s weight.
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………4
Total Visual Score….8 out of 12
Quality Remark: Low inner-grade, Low Dispersion.
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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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