Pre-Auction Analysis: October 7th, 2022, Sotheby’s Hong Kong, The Williamson Pink Star

Pre-Auction Analysis: October 7th, 2022, Sotheby’s Hong Kong, The Williamson Pink Star

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: 1115

Description: 11.15 ct, Cushion, Fancy Vivid Pink, IF. The Williamson Pink Star

High Auction Estimation: $ unavailable

Price Realized: $5,177,905 pc

Rarity: A Fancy Vivid Pink diamond of this weight, clarity, shape and color enters the market once every 25 years on average. Click Here

GIA Report: View 

Image and Video taken by Sotheby’s.

Analysis: 

A large Fancy Vivid Pink Cushion mixed-cut diamond, with a step-cut facet arrangement on the crown and a starburst on the bottom. This facet arrangement results in some colorless patches on the crown and a prominent colorless rhombus around the culet. The Inner-Grade is solid for a Vivid Pink, and the Undertone is typical for a straight pink fancy color diamond.

The surface face-up of the diamond is relatively large for an 11.15 carat and fairly corresponds to a higher carat weight.   

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

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.