Pre-Auction Analysis: November 8th, 2022, Christie’s Geneva

Our Christie’s Geneva 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: 2

Description: 9.53 carats, Round, Fancy Yellow, VS1 clarity

High Auction Estimation: $ 13,661 pc

Price realized: $15,434 pc

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

GIA Report: View

Analysis:

A 9.53 carat Fancy Yellow round diamond with a very large table (74%) and shallow pavilion (53%). The Inner-Grade seems to be very low, probably due to the low color retention caused by the stone’s proportions. The image shows the face-up view at a 45° angle, which implies the actual body color of this diamond in a much clearer way.

Visual Assets:

Inner Grade..……………….1

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….6 out of 12

Quality remark: Low Inner-Grade and Dispersion. 

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Lot: 3

Description: 6.04 ct, Emerald, Fancy Intense Yellow, VVS2

High Auction Estimation: $ 21,602 pc

Price realized: $29,644 pc

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

GIA Report: View

Analysis:

A Fancy Intense Yellow Emerald cut with a low color dispersion caused by a lack of facet modification on the pavilion to disperse color across a larger area. The Inner-Grade is strong, and a visible undertone is present in the yellow hue.

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………2

Total Visual Score….7 out of 12

Quality Remark: Low undertone and dispersion. 

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Lot: 12

Description: 10.28 ct, Marquise, Fancy Pink-Purple, I2

High Auction Estimation: $ 24,355 pc

Price realized: $29,872 pc

GIA Report: View

Analysis:

A large Marquise diamond with a striking number of visible inclusions. The purple body color is clearly seen on the face-up. It seems like the large amount of inclusions prevent the light from bouncing, reflecting, and reinforcing color as it should and as a result, the color is diffused.

*A side note about the clarity: 

The large, glacier-looking crack on one of the sides looks like a typical crack that occurred during the polishing process.

Visual Assets:

Inner Grade..……………….1

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….6 out of 12

Quality Remark: I2 clarity visible, low inner-Grade. 

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Lot: 71

Description: 18.18 ct, Pear, Fancy Vivid Pink, VVS2

High Auction Estimation: $ 1,932,264 pc

Price realized: $1,588,626 pc

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

GIA Report: View

Analysis: 

A Fancy Vivid Pink Pear-shaped diamond in a rare large size. The Inner-Grade of this large vivid pink is strong, and color is dispersed nicely in most of the face-up area. An elusive orange undertone is present in the hue, which prevents it from having a cooler pink “sweet flavor.” However, this doesn’t harm the overall color sensation and could meet our expectations of a pink fancy color diamond. 

The diamond’s crystal is saturated with graining and gives the stone a foggy look that overshadows its appearance. 

It is likely that the two easy-to-remove feathers on the crown were left there on purpose to avoid receiving the GIA remark “clarity based on internal graining,” thereby highlighting the fact that the stone is heavily grained to the point of affecting the clarity. 

The outline of the stone is not common and raises questions as to why the stone was made in this unconventional triangular shape. We can assume that other than yielding a bigger stone (and avoiding removing the two small feathers on the crown), the manufacturer was overly motivated to reach a symbolic weight (18.18), rather than completing the shape. 

*Side note about the GIA comment: “clarity is based on internal graining”: 

This remark is considered the “kiss of death” in many cases, especially in colorless diamonds with a high color grade. This remark appears only when the diamond has no other blemishes besides graining. For that reason, common practice in the industry is to leave small external feathers/inclusions, and as such, to avoid this remark.

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

Quality remark: Visible graining, odd shape.

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General

We use 1, 2, 3, 4, and 4+ to grade the three visual elements the 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, color dispersion is not a gemological quality and is the result of cutter proficiency.