Pre-Auction Analysis: April 4th and 5th 2023, Sotheby’s HK

Pre-Auction Analysis: April 4, 2023, Sotheby’s Hong Kong, Magnificent Jewels I

Our Sotheby’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: 1808

Description: 16.31 ct, Fancy Yellow, Radiant 

High Auction Estimation: $11,813 pc

Price realized: $9,920 pc

GIA Report: View

Analysis:

A 16.31 carat Fancy Yellow Radiant cut with a dark, colorless crown, creating a prominent frame around the table. The GIA report, dated 2008, indicates the color only. Viewing the stone under UV light reveals strong to very strong blue fluorescence. A cloud around the crown can be seen with the naked eye and the inner-grade is weak. 

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….8  out of 12

Quality remark: Strong blue fluorescence, low inner-grade

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Lot: 1827

Description: 10.01 ct, Fancy Intense Yellow, Radiant, VVS1

High Auction Estimation: $38,495 pc

Price realized: $33,943 pc

Rarity: 5-10 diamonds yearly – Share this rarity result – Here 

GIA Report: View

Analysis: 

A 10.01 carat Fancy Intense Radiant-cut diamond with very low color dispersion under the table and crown. Looking at the facet alignment, we can clearly see the remaining facets of what used to be a round brilliant that was repolished to a modified shape in order to reinforce the color. No significant undertone is present in the color.

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….8 out of 12

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Lot: 1828

Description: 3.07 ct, Fancy Light Orangy Pink, Pear, SI1

Description: 3.03 ct, Fancy Light Orangy Pink, Pear, VS2 

High Auction Estimation: $52,642 pc

Price realized: $39,785 pc

Rarity 3.07: 1-2 diamonds yearly – Share this rarity result – Here

Rarity 3.03: 1-3 diamonds yearly – Share this rarity result – Here

GIA Report 3.07: View

GIA Report 3.03: View

Analysis: 

A pair of Fancy Light Orangy Pink Pear-shaped diamonds with GIA reports from 2010. The carat millimeter dimensions are not an exact match. Several colorless patches are scattered around the diamonds’ face-up view. Their inner-grade and undertone are  unclear because both diamonds are mounted in pink gold and cannot be analyzed responsibly.    

Visual Assets 3.07:

Inner Grade..……………….N/A

Color Dispersion.………3

Undertone..…………………N/A

Total Visual Score….N/A

Visual Assets 3.03:

Inner Grade..……………….N/A

Color Dispersion.………3

Undertone..…………………N/A

Total Visual Score….N/A

Quality remark: Low compatibility 

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Lot: 1829

Description: 5.11 ct, Fancy Brownish Pink, Pear, VS1

High Auction Estimation: $87,977 pc

Price realized: $60,157 pc

Rarity: Once every 3-4 years – Share this rarity result – Here  

GIA Report: View

Analysis: 

A 5.11 carat Fancy Pink Pear-shaped diamond with a brown modifier, with a GIA report dated 2010. The diamond is mounted in a large pink cup which reflects inside the crystal. It is impossible to isolate the diamond’s true color from the gold reflection. We were therefore unable to determine the undertone and the inner-grade. 

Visual Assets:

Inner Grade..……………….N/A

Color Dispersion.………3

Undertone..…………………N/A

Total Visual Score….N/A

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Lot: 1837

Description: 8.08 ct, Fancy Vivid Yellow, Emerald, VS2 

High Auction Estimation: $71,536 pc

Price realized: $60,071 pc

Rarity: 4-8 diamonds yearly – Share this rarity result – Here

GIA Report: View

Analysis:

A 8.08 carat Fancy Vivid Yellow Emerald-cut diamond. The diamond was cut and polished as a traditional colorless diamond,  resulting in low color dispersion. The inner-grade is very strong, and no significant undertone is seen in the hue. The depth is 71%. 

Visual Assets:

Inner Grade..……………….4

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….9 out of 12

Quality remark: Low dispersion 

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Lot: 1847

Description: 8.85 ct, Fancy Deep Yellow, Heart, VS1 

High Auction Estimation: $13,062 pc

Price realized: $17,368 pc

Rarity: 1-3 diamonds yearly – Share this rarity result – Here 

GIA Report: View

Analysis:

A 8.85 carat Fancy Deep Yellow Heart-shaped diamond with several colorless patches on the crown. The warm undertone and high inner-grade this diamond exhibits are inherent among yellow fancy color diamonds graded as deep.  

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

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Lot: 1852

Description: 11.88 ct, Fancy Vivid Yellow, Radiant, IF

High Auction Estimation: $64,872 pc

Price realized: $58,561 pc

Rarity: 2-3 diamonds yearly – Share this rarity result – Here 

GIA Report: View

Analysis:

An 11.88 carat Vivid Yellow Mixed-cut Radiant. The color dispersion is very high and no undertone is visible in the hue. The inner-grade is moderate .  

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………4

Undertone..…………………4

Total Visual Score….10 out of 12

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Lot: 1853

Description: 5.49 ct, Fancy Intense Blue, Oval, IF 

High Auction Estimation: $1,170,726pc

Didn’t reach the minimum

Rarity: Once every 8-12 years – Share this rarity result – Here 

GIA Report: View

Analysis:

A 5.49 carat Fancy Intense Blue Mixed-cut Oval with step facets on the crown and a Starburst facet alignment on the pavilion. A gray undertone is visible in the hue and the inner-grade is strong.     

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………2

Total Visual Score….8 out of 12

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Lot: 1884

Description: 5.85 ct, Fancy Vivid Yellow, Radiant, IF

High Auction Estimation: $57,214 pc

Price realized: $47,016 pc

Rarity: 3-6 diamonds yearly – Share this rarity result – Here 

GIA Report: View

Analysis: 

A 5.85 carat rounded-corner Mixed-cut Fancy Vivid Yellow. The stone has four dark, colorless patches on the crown and one in the culet. The inner-grade is strong and no significant undertone is present in the color. 

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

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Lot: 1886

Description: 36.25 ct, Fancy Vivid Yellow, Cushion, VVS2 

High Auction Estimation: $80,911 pc

Price realized: $63,239 pc

Rarity: 1-2 diamonds yearly – Share this rarity result – Here 

GIA Report: View

Analysis:

A large, elongated Vivid Yellow with a colorless crown. The inner-grade is strong and no significant undertone is visible in the color.  

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

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Lot: 1892

Description: 11.17 ct, Fancy Pink, Pear, VVS1 

Description: 10.85 ct, Fancy Pink, Pear, VVS1 

High Auction Estimation: $320,808 pc 

Price realized: $279,112 pc

Rarity 11.17: Once every 3-4 years – Share this rarity result – Here

Rarity 10.85: Once every 3-4 years – Share this rarity result – Here

GIA Report 11.17: View

GIA Report 10.85: View

Analysis:

Two large Fancy Pink Pear-shaped diamonds with matching dimensions, tables, and depths, but different visual assets. The 11.17 carat has a weak inner-grade and dispersion, while the 10.85 exhibits stronger features. The undertone cannot be reliably determined, as the pavilion of both stones is covered with pink gold. 

Visual Assets 11.17:

Inner Grade..……………….2

Color Dispersion.………2

Undertone..…………………2

Total Visual Score….6 out of 12

Visual Assets 10.85:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

Quality remark: Low compatibility 

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Lot: 1893

Description: 10.05 ct, Fancy Vivid Purplish Pink, Cushion, VS2

High Auction Estimation: $2,129,403 pc

Withdrawn from auction

Rarity: Once every 25 years or more – Share this rarity result – Here 

GIA Report: View

Analysis:

An important Fancy Vivid Purplish Pink Cushion-cut diamond. The inner-grade seems weak, although it is supported by a large pink gold cup that covers the pavilion. The dispersion is high, and the purple modifier creates a pleasant, cool undertone.   

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………4

Undertone..…………………3

Total Visual Score….9 out of 12

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Pre-Auction Analysis: April 5, 2023, Sotheby’s Hong Kong, 50th Anniversary Luxury Evening Auction: The Exceptionals

Lot: 87

Description: 133.04 ct, Fancy Vivid Yellow, Cushion, VS2 

High Auction Estimation: $67,495 pc

Withdrawn from auction

GIA Report: View

Analysis:

The original 139.38 carat diamond had an interesting provenance. It was sold for 1.32 million Swiss francs by Christie’s Geneva in 1983. Upon inspecting its facet alignment, it appears that the diamond underwent modifications to reinforce its color and lost 6 carats, resulting in it being graded a Fancy Vivid Yellow. The GIA plot clearly displays the modifications made to partially transform the diamond into a modern gem.

The modifications resulted in an unbalanced appearance of the diamond’s face up view, as most of the color is concentrated in the table, leaving a large, colorless crown. The 72% depth is a typical attribute of the previous antique cut, and the diamond displays a small outline relative to its weight. 

The diamond’s inner-grade is strong, and no green or brown undertone is present in its hue. 

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………4

Total Visual Score….9 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.