Pre-Auction Analysis: Christie’s Geneva, May 15th, 2024

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 14 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 5

Description: 9.55 ct, Fancy Vivid Yellow, Cushion, VS1
High Auction Estimation: $34,502 pc
Price Realized: $73,003 pc
Reports: GIA, Rarity, Diary
True Face-Up: equivalent to that of a ~ 12.8 carat – 34.2% larger than the average 

Analysis: A 9.55 ct Vivid Yellow cushion cut diamond that features an old mine facet alignment on the pavilion and a modern cut crown, likely modified in the recent decade to enhance color saturation. The Inner Grade is solid, and the yellow color leans towards the cooler spectrum. The multiple colorless patches live in harmony with the old look and feel of this diamond.

Visual Assets:
Inner Grade..……………….4
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….9 out of 12

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Lot 67

Description: 8.01 ct, Fancy Deep Yellow-Orange, Oval, SI1
High Auction Estimation: $89,125 pc
Price Realized: $69,600 pc
Reports: GIA, Rarity, Diary
True Face-Up: equivalent to that of a ~11 carat  – 37.3% larger than the average

Analysis: An 8.01-carat oval displays approximately 40% yellow and 60% orange color. Its dark tone has earned the description “Deep”, and a minor brown Undertone is present in the mix. The area around the culet is considered a *colorless patch because it disrupts the uniformity of the color Dispersion. It was likely cut this way in an attempt to insert brighter reflections and achieve the “Vivid” grade. The medium yellow fluorescence is a supporting attribute that makes the stone more appealing.

* Significant areas that are at least two saturation grades below the darker ones will be considered as colorless patches.

Visual Assets:
Inner Grade..……………….4
Color Dispersion.………2
Undertone..…………………2
Total Visual Score….8 out of 12

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Lot 106

Description: 202.18 ct, Fancy Intense Yellow, Pear, SI1
High Auction Estimation: $19,785 pc
Price Realized: $33,400 pc
Reports: GIA, Diary
True Face-Up: Slightly smaller but within standard

Analysis: An enormous and impressive Intense Yellow diamond. Yet, the visible inclusion and the unstable Dispersion might diminish the sense of greatness expected from a diamond of this magnitude. Concessions and compromises appear to have been made to maintain a weight of over 200 carats, which explains why the cutter did not achieve the precise angle on the pavilion, resulting in an elusive empty reflection in the center. Additionally, some inclusions that could have been removed with approximately 5-10% weight loss were left in place. The Inner Grade is solid, with no significant amount of green or brown Undertone.

Visual Assets:
Inner Grade..………………3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: Not eye clean 

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Discover the IDU Grading Standard

Our pre-auction analysis leverages the IDU Grading Standard to evaluate fancy color diamonds, focusing on three key visual attributes not covered by GIA: Inner-Grade, Undertone, and Color Dispersion. These elements provide deeper insights into a diamond’s color intensity, hue influences, and color evenness—factors critical to its beauty and value. Additionally, our True Face-Up calibration reveals how a diamond’s carat weight translates to its visual presence.

Inner-Grade measures the saturation strength within the GIA-defined categories, providing insights into the color’s intensity and richness. From Grade 1, indicating the faintest saturation, to Grade 4+, reserved for the most vivid saturation levels, this grading reveals the depth of a diamond’s color.

Color Dispersion examines how evenly the color is distributed across the diamond’s face-up view. This aspect ranges from Grade 1, showing noticeable colorless areas, to Grade 4+, indicating a flawless color spread.

Undertone evaluates the subtle hue influences within the diamond’s color. The undertone grade reflects the diamond’s color fidelity and its alignment with the desirable aesthetic standards.

From Grade 1, indicating a significant presence of altering hues that might dilute the primary color’s intensity. to Grade 4+, reserved for diamonds where the undertone enhances the primary color, making it exceptionally desirable.

Our innovative True Face-Up calibration grade also offers invaluable insights into how a diamond’s carat weight is presented visually, adding another dimension to our comprehensive analysis.

For an in-depth exploration of our grading methodology and how it enhances the valuation of fancy color diamonds, we invite you to read the full article.