Magnificent Jewels
Our Christie’s Hong Kong 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: 1838
Description: 3.01 ct, Fancy Yellow, Cushion, SI1 Rarity, GIA
Analysis:
A 3.01 carat fancy yellow cushion cut with a very large colorless crown and several black crystals under the table. The symmetry is Fair.
High Auction Estimation: $21,220 pc
Price realized: $9,086 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………2
Total Visual Score….7 out of 12
Quality remark: low dispersion, Fair symmetry
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Lot: 1840
Description: 12.63 ct, Fancy Yellow, Radiant, VS2 Rarity, GIA
Analysis:
A large fancy yellow radiant cut with a 75% table, surrounded by a small colorless crown. Inner-grade is strong and no undertone is visible in the hue. The face-up view appears larger in relation to its carat weight.
High Auction Estimation: $12,137 pc
Price realized: $15,285 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12
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Lot: 1841
Description: A pair of earrings with two Fancy Yellow diamonds of Oval cut weighing 7.13 ct and 7.03 ct.
Analysis:
Two fancy yellow oval-cut diamonds with the same measurements and dispersion; however, these two ovals could not be defined as “matching” because the 7.03ct has a much warmer undertone, thereby eliminating the premium paid for two identical diamonds.
Total High Auction Estimation: $70,218 Total
Price realized: $176,954 Total
Visual Assets 7.13 ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Visual Assets 7.03 ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………1
Total Average Score….7 out of 12
Quality remark: not matching
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Lot: 1842
Description: 1.12 ct, Fancy Light Gray-Blue, Marquise, SI2, GIA
Analysis:
A 1.12 fancy light blue with 40% gray in the hue. Symmetry is Fair and clarity is SI2. As the stone is completely covered with gold and it was impossible to analyse the visual features.
High Auction Estimation: $56,985 pc
Didn’t reach the minimum
Visual Assets:
Inner Grade..……………….N/A
Color Dispersion.………N/A
Undertone..…………………N/A
Total Visual Score….N/A
Quality remark: Fair symmetry, SI2
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Lot: 1843
Description: 1.23 ct, Fancy Intense Bluish Green, Cushion, VS2 Rarity, GIA
Analysis:
An intense Green diamond with a blue modifier giving this diamond a turquoise color sensation. The small table (59%) surrounded with a steep-angled crown, creates a large colorless frame around the table. The brown patches on the diamond are not marked on the GIA plot and are common in natural green diamonds.
High Auction Estimation: $155,671 pc
Didn’t reach the minimum
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: 1844
Description: 2.03 ct, Fancy Vivid Yellow, Cushion, SI2 Rarity, GIA
Analysis:
A vivid yellow cushion cut diamond with 62% depth and no brown or green undertone in the hue. Clarity is SI2.
Total High Auction Estimation: $48,515 Total
Price realized: $45,043 Total
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….9 out of 12
Quality remark: SI2 clarity
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Lot: 1900
Description: 3.02 ct, Fancy Vivid Yellow, Emerald, VVS2 Rarity, GIA
Analysis:
A 3.02 vivid yellow Square Emerald cut diamond with no modification in the cut and a warm yellow undertone.
High Auction Estimation: $229,812 Total
Price realized: $225,215 Total
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………2
Undertone..…………………2
Total Visual Score….8 out of 12
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Lot: 1903
Description: 7.36 ct, Fancy Vivid Yellow, Emerald, VVS2 Rarity, GIA
Analysis:
A square vivid yellow Emerald cut diamond exhibiting a large face up in relation to its carat weight. Color dispersion is low.
High Auction Estimation: $112,747 pc
Price realized: $98,357 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.….……1
Undertone..…………………3
Total Visual Score….7 out of 12
Quality remark: low color dispersion
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Lot: 1912
Description: 22.43 ct, Fancy Blue, Radiant, VVS2 Rarity, GIA
Analysis: a very large fancy blue radiant cut diamond with a prominent colorless frame in the crown area. The inner-grade is weak and a gray undertone is visible in the hue.
High Auction Estimation: $216,316 pc
Didn’t reach the minimum
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………2
Total Visual Score….6 out of 12
Quality remark: A bit grey
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Lot: 1925
Description: 8.92 ct, Fancy Vivid Yellow-Orange, Pear, IF Rarity, GIA
Analysis:
A large vivid orange pear shape with a yellow modifier. The color is dispersed evenly throughout the face up of the stone and the inner-grade is strong. The yellow fluorescence creates a pleasant color sensation.
High Auction Estimation: $429,440 pc
Price realized: $455,656 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….9 out of 12
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Lot: 1952
Description: 4.08 ct, Fancy Intense Pink, Pear, IF Rarity, GIA
Analysis:
A fancy intense pink pear shape with a cold and pleasant undertone. The inner-grade is strong and large colorless patches are situated on the crown. The GIA report is dated 2012.
High Auction Estimation: $1,095,387 pc
Price realized: $977,257 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….7 out of 12
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Lot: 1953
Description: 4.83 ct, Fancy Vivid Blue, Pear, IF Rarity, GIA
Analysis:
A vivid blue brilliant cut pear shape with a typical large colorless “butterfly” in the center. Very little gray undertone is visible in the hue and the inner-grade is low.
High Auction Estimation: $2,115,787 pc
Price realized: $1,821,909 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….7 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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