Pre-Auction Analysis: December 6th, 2022, Christie’s NY

Pre-Auction Analysis: December 6th, 2022, Christie’s New York, Magnificent Jewels

Our Christie’s New York 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: 20

Description: 104.04 ct, Fancy Intense Yellow, Pear, IF

High Auction Estimation: $24,029 pc

Price realized: $21,915 pc

GIA Report: View

Analysis: 

A very large Fancy Intense Yellow diamond. The GIA classified the shape as a Pear however,  we had difficulty finding similarities to this shape. The face-up surface is very small relative to the weight (with a 75.2% depth), and it seems that the manufacturer prioritized its weight over a standard appearance. The Inner-Grade is strong, and many colorless patches are seen from the face-up. No significant undertone is visible.   

*The diamond was offered at the Geneva sale in July 2020 by Christie’s.

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….8 out of 12

Quality Remark: Odd shape, 75% depth

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Lot: 22

Description: 14.41 ct, Fancy Intense Yellow, Radiant, VVS2

High Auction Estimation: $20,818 pc

Price realized: $24,483 pc

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

GIA Report: View

Analysis:

A 14.41 carat Fancy Intense Yellow Radiant cut, with a large face-up surface relative to its weight and high visual assets on all three parameters. This combination of high visual assets and a large appearance is rare.

*The yellow gold cup underneath the diamond can be seen clearly in the video when tilting the ring. This may have affected the Inner-Grade during the analysis. 

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………4

Undertone..…………………4

Total Visual Score….11 out of 12

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Lot: 55

Description: 8.15 ct, Fancy Yellow, Radiant, VS2

High Auction Estimation: $9,815pc

Price realized: $10,823 pc

Rarity: 12-15 diamonds yearly – Share this rarity result – Here

GIA Report: View

Analysis:

An 8.15 Fancy Yellow Radiant cut with some colorless areas on the crown, a strong Inner-Grade, and no significant undertone in the color.

The GIA report is dated 2008.

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

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Lot: 63

Description: 13.75 ct, Fancy Vivid Yellow, Emerald, IF

High Auction Estimation: $130,909 pc

Price realized: $91,637 pc

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

GIA Report: View

Analysis:

A large Vivid Yellow Emerald-cut diamond with a weak Inner-Grade. No significant undertone is visible in the color and color dispersion is average. The stone has a De Beers laser inscription on its girdle.

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….8 out of 12

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Lot: 75 

Description: 2.21 ct, Fancy Intense Blue, Oval, VVS2

High Auction Estimation: $814,479 pc

Price realized: $1,058,824 pc

Rarity: Once every 5-6 years – Share this rarity result – Here

GIA Report: View

Analysis: 

An antique Fancy Intense Blue Oval. Heavily scratched on the table facet, a sign that the stone was used in many occasions over a period of many years. The Inner-Grade is very strong, and had the stone been presented without a GIA report, one could have thought it was a Fancy Vivid Blue. No gray undertone is present in the hue.

Visual Assets:

Inner Grade..……………….4

Color Dispersion.………3

Undertone..…………………4

Total Visual Score….11 out of 12

Quality Remark: Heavy wear

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Lot: 76 – Mysteriously withdrawn 

Description: 13.15 ct, Fancy Vivid Pink, Emerald, VVS1

High Auction Estimation: $2,661,596 pc

Rarity: Once every 16-20 years – Share this rarity result – Here  

GIA Report: View

Analysis:

This important Vivid Pink diamond was mysteriously withdrawn from sale under circumstances shrouded in secrecy.  

Visual Assets:

Inner Grade..……………….N/A

Color Dispersion.………N/A

Undertone..…………………N/A

Total Visual Score….N/A

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Lot: 81 

Description: 3.10 ct, Fancy Gray-Blue, Round, VS2

High Auction Estimation: $161,290 pc

Price realized: $105,678 pc

GIA Report: View

Analysis:

A Fancy Gray-Blue Round Brilliant-cut diamond with split facets on the pavilion. Fancy color diamonds with a gray modifier usually receive a strong Inner-Grade as is the case here. According to the GIA report, blue is the body color, although a strong gray sensation dominates the face-up view of the stone. Two prominent black inclusions are visible under the table.   

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………2

Total Visual Score….8 out of 12

Quality Remark: Vs2 : strong gray undertone, black VS2

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Lot: 83 

Description: 3.01 ct, Fancy Gray-Violet, Round, I2

High Auction Estimation: $166,112 pc

Withdrawn from auction

GIA Report: View

Analysis:

A Round Fancy Gray-Violet diamond. According to the GIA color description, the stone is 40% gray and 60% violet, while the color dominating the face-up view is gray. The stone’s heavy inclusions impact light reflection and create a cloudiness. 

Visual Assets:

Inner Grade..……………….N/A

Color Dispersion.………N/A

Undertone..…………………N/A

Total Visual Score….N/A

Quality remark: I2 clarity, Gray sensation with low translucency 

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Lot: 105 

Description: 5.00 ct, Fancy Vivid Blue, Pear, VS1

High Auction Estimation: $800,000 pc

Withdrawn from auction

Rarity: Once every 5-6 years – Share this rarity result – Here 

Analysis:

A very flat Vivid Blue Briolette diamond. The blue color is seen only around the edges of the shape, while most of the stone’s surface is completely colorless. No gray undertone is visible in the hue.  

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………1

Undertone..…………………4

Total Visual Score….7 out of 12

Quality remark: poor color dispersion

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Lot: 110 

Description: 107.46 ct, Fancy Yellow, Radiant, VS2

High Auction Estimation: $23,264 pc

Price realized: $24,009 pc

GIA Report: View

Analysis:

A very large Old Mine Cushion-cut diamond that was re-polished to reinforce its saturation on the four reflecting pavilion facets. Most of the face-up surface is colorless or with large black areas. The depth is 74%, which is typical of an Old Mine diamond. 

The stone was offered by Christie’s at the Geneva auction in November, 2020.

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………1

Undertone..…………………3

Total Visual Score….6 out of 12

Quality remark: poor color dispersion.

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Lot: 112

Description: 10.26 ct, Fancy Yellow, Radiant, VS1

High Auction Estimation: $14,619 pc

Price realized: $12,895 pc

Rarity: 6-11 diamonds yearly – Share this rarity result – Here  

GIA Report: View

Analysis:

A 10.26 Radiant-cut diamond with an old fashioned (1980-90s) facet arrangement of the pavilion, leaving many colorless areas. The Inner-Grade is strong, and the surface area appears larger relative to its weight.  

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….8 out of 12

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Lot: 113 

Description: 1.01 ct, Fancy Vivid Orange, Radiant, SI2

High Auction Estimation: $594,059 pc

Price realized: $661,189 pc

GIA Report: View

Analysis:

A Fancy Vivid Orange Radiant cut with a very strong Inner-Grade and high color dispersion. Black and colorless inclusions are scattered under the table, giving this diamond an SI2 clarity grade. 

Visual Assets:

Inner Grade..……………….4

Color Dispersion.………4

Undertone..…………………4

Total Visual Score….12 out of 12

Quality Remark: SI2 with Black inclusions 

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Lot: 114

Description: 31.62 ct, Fancy Blue, Pear, VVS1

High Auction Estimation: $474,383 pc

Price realized: $374,447 pc

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

GIA Report: View

Analysis:

A very large Fancy Blue Pear-shaped diamond with a significant amount of gray undertone in its color. The Inner-Grade is weak, and large colorless areas are seen around the crown. However, the face-up surface appears larger relative to its weight. 

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………3

Undertone..…………………2

Total Visual Score….7 out of 12

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Lot: 115 

Description: 8.22 ct, Fancy Vivid Yellow, Round, VS1

High Auction Estimation: $30,413 pc

Price realized: $52,117 pc

Rarity: Once every 1-2 years – Share this rarity result – Here 

GIA Report: View

Analysis: 

Looking at the facet alignment, the large open culet, and the absence of a girdle on this modified Round Vivid Yellow diamond, we understand that the stone was repolished from what used to be an Old Mine Cushion-cut from two centuries ago. 

The color is visible mainly through the table, while the crown is mostly colorless. The Inner-Grade is strong, and an attractive orange undertone is present in the color.   

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………4

Total Visual Score….9 out of 12

Quality Remark: low dispersion 

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Lot: 130 

Description: A Yellow fancy color diamond necklace – 5 diamonds have a GIA report

High Auction Estimation: $600,000 total

Price realized: $1,071,000 Total

GIA Reports: View

Analysis:

An impressive collection of 35 Yellow Fancy Color Ovals laid out in a Riviera necklace.  

The saturation of the five center stones is inconsistent, combining Fancy Yellow and Intense Yellow with different ratios. Strangely, the other diamonds in this collection are not accompanied by GIA reports, which raises doubt about their color and quality. Buyers should inspect all stones carefully. The length-to-width ratio of most of the stones in this layout appears very short and is considered to be less in-demand. 

Visual Assets:

Inner Grade..……………….N/A

Color Dispersion.………N/A

Undertone..…………………N/A

Total Visual Score….N/Z

Quality remark: only 5 out of 35 stones have a GIA report. Short ratio for most Ovals

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Lot: 133 

Description: 5.42 ct, Fancy Greenish Blue, Pear, I2

High Auction Estimation: $129,151 pc

Price realized: $$116,237 pc

GIA Report: View

Analysis: 

A Fancy Greenish-Blue Pear shape with I2 clarity caused by many inclusions and a large feather penetrating from the girdle into the crown. The strong blue fluorescence creates a sort of blue veil over the face-up view, dimming its sparkle. 

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………4

Total Visual Score….10 out of 12

Quality Remark: I2 clarity and strong blue fluorescence

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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.