Pre-Auction Analysis: Christie’s Hong Kong, May 27th, 2024

Pre-Auction Analysis: Christie’s Hong Kong, May 27th, 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 1851

Description: 2.05 ct, Fancy Purplish Pink, Oval, SI2
GIA, Rarity, Diary
True Face-Up: Distinctly Smaller than Standard.

Description: 2.01 ct, Fancy Purple-Pink, Oval, SI2
GIA, Rarity, Diary
True Face-Up: Significantly Smaller than Standard.

High Auction Estimation: $640,000 total
Price Realised: $419,637 total

Analysis: Two pink oval-cut diamonds with purple modifiers, both with SI2 clarity, appear significantly smaller in relation to their weight. Large colorless patches are visible on the crown, reducing the overall aesthetic of the diamonds.

Quality Remark: Small face-up, SI2

Quality Remark: Very small face-up, SI2

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Lot 1852

Description: 0.52 ct, Fancy Purplish Red, Radiant, SI2
High Auction Estimation: $865,385 pc
Price Realised: $806,984 pc
GIA, Diary
True Face-Up: True to its carat weight.

Analysis: A 0.52-carat Fancy Purplish Red Radiant-cut diamond accompanied by a GIA report dated 2016 features an Argyle logo inscribed on the girdle along with the French text ‘LE TENDER MMVIII LE PETIT ROUGE’ (Tender 2008 The Small Red), suggesting the diamond was acquired at the 2008 tender. However, after clarifying with Argyle, we can confirm that this inscription was not made by the mine. The hue shows no significant brown Undertone.

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Lot 1853

Description: 1.01 ct, Fancy Intense Blue, Heart, I1
GIA, Rarity, Diary
True Face-Up: Equivalent to that of a 1.435 carat ~42.2% larger

Description: 1.01 ct, Fancy Intense Pink-Purple, Heart, SI2
GIA, Rarity, Diary
True Face-Up: Equivalent to that of a 1.355 carat ~34.5% larger

High Auction Estimation: $740,000 total
Price Realised: $564,889 total

Analysis: A ‘Moi et Toi’ ring that features blue and pink purple heart shapes with distinctly different outlines. The Inner Grade of the blue heart is very low, and much of its crown appears colorless. No significant gray Undertone is present in the hue. The Intense Pink Purple displays a pleasant color sensation but has a significant amount of colorless areas.

Quality Remark: I1 clarity

Quality Remark: SI2 clarity. 

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Lot 1855 

Description: 5.01 ct, Fancy Orangy Pink, Pear, VVS1
GIA (not available)

Description: 5.01 ct, Fancy Light Bluish Green, Pear, VVS1
GIA, Rarity, Diary
True Face-Up: Equivalent to that of a 5.695 carat ~13.6% larger

High Auction Estimation: $1,900,000 total
Price Realised: $1,287,974 total

Analysis: A ‘Moi et Toi’ ring that features two pear-shaped diamonds: one Orangy Pink and one Light Bluish Green. The Fancy Orangy Pink has average visual assets, while the Fancy Light Bluish Green appears to have a weak Inner Grade.

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Lot 1893

Description: 5.27 ct, Fancy Vivid Yellow, Emerald,  IF
High Auction Estimation: $62,619 pc
Price Realised: $52,061 pc
GIA, Rarity, Diary
True Face-Up: Equivalent to that of a 7.515 carat ~42.6% larger

Analysis: A Vivid Yellow Emerald-cut diamond that features a significantly large face-up relative to its weight. The Vivid Inner Grade is very strong, while the dispersion is low due to a minor modification on the pavilion. No significant green or brown Undertone is visible in the hue.

Quality Remark: Low dispersion 

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Lot 1894

Description: 29.49 ct, Fancy Vivid Yellow, Emerald, VVS1
High Auction Estimation: $77,993 pc
Price Realised: $67,323 pc
GIA, Rarity, Diary
True Face-Up: Equivalent to that of a 31.94 carat ~8.3% larger

Analysis: A very large square Vivid Yellow Emerald-cut diamond that presents a face-up view 8% larger than its full scale potential. Mounted in a ring, the Color Dispersion displays a high grade for a step-cut fancy-color diamond. The Inner Grade is strong, and no green or brown Undertone is visible in the hue.

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Lot 1897

Description: 3.33 ct, Fancy Deep Blue, Cushion, IF
High Auction Estimation: $3,200,000 total
Price Realised: $2,217,810 total
GIA (not available)

Analysis: A high Inner Grade is inherent due to the deep saturation. A few colorless patches are visible through the table and a small amount of gray Undertone is visible in the hue.

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Lot 1898

Description: 4.63 ct, Fancy Intense Purplish Pink, Radiant, I1
High Auction Estimation: $69,115 pc
Price Realised: Didn’t reach the minimum
GIA Rarity Diary
True Face-Up: Subtly Smaller than Standard

Analysis: A 4.63 ct Fancy Intense Purplish Pink radiant-cut diamond that features a low Inner Grade with some colorless patches on the crown. The cool purple modifier, in combination with the pink body color, results in a pleasant Undertone. Despite its I1 clarity and strong blue fluorescence, they do not exert a substantial negative impact on the overall appearance.

Quality Remark: I1 clarity/Strong Blue

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Lot 1899

Description: 2.68 ct, Fancy Vivid Purplish Pink, Radiant, IF
High Auction Estimation: $2,388,060 pc
Price Realised: $1,608,226 pc
GIA, Rarity, Diary
True Face-Up: Equivalent to that of a 2.765 carat ~3.2% larger

Analysis: A Fancy Vivid Purplish Pink radiant-cut diamond with high visual assets features a strong Inner Grade, high Color Dispersion, and a very pleasant Undertone that meets the expectations for a diamond with this color description. Additionally, its visual presence appears slightly higher than its carat weight would suggest.

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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, determining the level of saturation. 

Grade 1 places the saturation in doubt, indicating it borders on the saturation below. 

Grade 2 is a weak saturation, 

Grade 3 refers to a solid saturation, 

Grade 4 borders on one saturation above.

Grade 4+ is reserved for exceptional saturation in the vivid category.

Color Dispersion examines literally how well the color mosaic is dispersed across the diamond’s face-up view. 

This aspect ranges from Grade 1, showing noticeable colorless areas, to Grade 4+, indicating perfect dispersion.

Undertone evaluates the subtle color influences within the diamond’s color, such as brightness or muted tones. 

The undertone grade reflects the diamond’s color sensation and how well it meets our expectations of the color. 

Grade 1 indicates a significant presence of another color. 

Grade 2 indicates a mild foreign sensation. 

Grade 3 indicates an insignificant undertone (most abundant). 

Grade 4 is the pure form of the color.

Grade 4+ is reserved for pink diamonds where the undertone enhances the primary color, making it exceptionally desirable.

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.