Magnificent Jewels
Our Christie’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: 7
Description: 8.31 ct, Fancy Vivid Yellow, Square, VS1.
Analysis: A square vivid yellow emerald cut with a low inner grade and a typical color dispersion for a step cut. The diamond has a strong blue fluorescence.
High Auction Estimation: $30,084 pc
Price Realised: $30,325 pc
Visual Assets:
Inner Grade..……………….2
Color Dispersion ..….…3
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: strong blue fluorescence
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Lot: 12
Description: 19.18 ct, Fancy Yellow, Oval, SI1.
Analysis: A large fancy yellow oval cut diamond from the middle of the 20th century. The facet alignment, taken from the classic colorless world, results in a large colorless bowtie. The inner grade is weak, and no substantial green or brown undertone is visible in the hue.
High Auction Estimation: $10,428 pc
Price Realised: $302,400 Total
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: low color dispersion
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Lot: 30
Description: 2.06 ct, Fancy Vivid Orange, Oval, I1.
Analysis: A relatively large, vivid orange oval diamond with I1 clarity, resulting from various inclusions and cavities. The inner grade is very strong, also due to a warm color sensation. The yellow fluorescence contributes to the overall appearance.
High Auction Estimation: $291,262 pc
Price Realised: $360,874 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.….……3
Undertone..…………………2
Total Visual Score….9 out of 12
Quality Remark: I1 clarity
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Lot: 31
Description: 2.06 ct, Fancy Deep Blue, Pear, VS1.
Analysis: A fancy deep blue pear shape with a few colorless patches and a small amount of gray undertone.
High Auction Estimation: $291,262 pc
Price Realised: $581,068 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….8 out of 12
Quality Remark: gray undertone
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Lot: 38
Description: 4.31 ct, Fancy Dark Bluish Gray, Pear, IF.
Analysis: A fancy dark bluish gray with a small colorless bowtie. The color corresponds with the GIA color description.
High Auction Estimation: $162,413 pc
Price Realised: Didn’t reach the minimum
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark:
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Lot: 47
Description: 1.35 ct, Fancy Deep Pink, Round, SI1.
Analysis: Highly saturated round pink diamonds above one carat are rare finds on the market and are highly sought after by savvy collectors. This unique diamond exhibits a strong color with a warm undertone in the hue and relatively high dispersion.
High Auction Estimation: $111,111 pc
Price Realised: $168,000 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….9 out of 12
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Lot: 48
Description: 2.16 ct, Fancy Deep Blue, Round, VVS2.
Analysis: A relatively large deep blue round brilliant with a typical color dispersion for a round fancy color diamond and a visible gray undertone.
High Auction Estimation: $694,444 pc
Price Realised: Didn’t reach the minimum
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….8 out of 12
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Lot: 52
Description: 5.16 ct, Fancy Vivid Yellowish Orange, Pear, VS2.
Analysis: A large, vivid orange pear-shaped diamond with a yellow modifier in the hue. Although the facet arrangement does not create an ideal color dispersion, the high inner grade compensates for this issue. The yellow fluorescence gives the diamond a nice, bright color sensation.
High Auction Estimation: $387,597 pc
Price Realised: $326,260 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….10 out of 12
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Lot: 74
Description: 12.03 ct, Fancy Intense Yellow, Square, VVS1.
Analysis: A Radiant cut diamond featuring an unusual modified outline. Observing the facet alignment, we can assume that the diamond was recut from a classic traditional shape. The crown is predominantly colorless, with the color concentrated within the table. Since the diamond is entirely encased in a gold cup, we were unable to determine the level of its inner grade and undertone.
High Auction Estimation: $12,469 pc
Price Realised: $201,600 Total
Visual Assets:
Inner Grade..……………….N/A
Color Dispersion.………3
Undertone..…………………N/A
Total Visual Score….N/A
Quality Remark: low dispersion
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Lot: 76
Description: 61.47 ct, Fancy Greenish Yellow, Radiant, VS2.
Analysis: Fancy greenish-yellow diamonds of this size are a rare find. The facet alignment in this radiant cut was not executed meticulously, resulting in a very large colorless crown. The presence of clouds within the diamond affects its translucency and sparkle, elements that are particularly crucial for diamonds of such substantial size.
High Auction Estimation: $16,268 pc
Price Realised: $25,419 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………2
Total Visual Score….7 out of 12
Quality Remark: Clouds impact translucency – low dispersion
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Lot: 97
Description: 1.4 ct, Fancy Dark Gray-Blue, Square, VVS1.
Analysis: A 1.41-carat square emerald cut diamond, featuring approximately 40% gray and 60% blue. Step-cut diamonds are often chosen for fancy-color diamonds that exhibit dark hues, as they are known to retain a low amount of color. Diamonds with darker colors, like this one, inherently receive a high inner grade.
High Auction Estimation: $178,571 pc
Price Realised: $171,000 pc
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….8 out of 12
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Lot: 99
Description: 3.49 ct, Fancy Vivid Blue, Cushion, IF.
Analysis: A cushion-shaped diamond fashioned in the style of an old-mine-cut. The vivid hue of this diamond borders on a deep blue color grade, often referred to as ‘ink-blue’. Its dispersion is high compared to typical old-mine-cut diamonds, and there is very little visible gray undertone in the mix.
High Auction Estimation: $1,575,931 pc
Price Realised: $1,574,499 pc
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….10 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, 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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