Pre-Auction Analysis: September 13th, 2022, Sotheby’s New York – Important Jewels

Our Sotheby’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.

__________________________________________________________________________

Lot: 67

Description: 12.84 ct, Fancy Yellow, Cushion, SI1
High Auction Estimation: $9345 pc

Price Realized: $14,709 pc

Rarity: A small number of similar diamonds enter the market yearly… Check Rarity Here 
GIA Report: View

Analysis:
A large Fancy Yellow Cushion-cut diamond with pointed corners.  The stone’s face-up area appears much larger than most fancy color cushion cut diamonds in this weight category. The Inner-Grade is high, and no brown or green Undertone can be seen in its hue. Several large colorless areas can be seen through the table. The SI1 grade is a result of two feathers on the pavilion.

Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12

__________________________________________________________________________

Lot: 71

Description: 5.25 ct, Fancy Vivid Yellow, Emerald, VVS1 
High Auction Estimation: $42,857 pc

Price Realized: $72,000 pc

Rarity: A small number of similar diamonds enter the market yearly… Check Rarity Here 
GIA Report: View 

Analysis:
A 5.25 Vivid Yellow Emerald-cut diamond (1.07 ratio) with exceptional visual characteristics. The Inner-Grade is very high and the yellow hue is absolute. The few colorless areas that are visible are typical of this cut, thus it receives a high grade as well.

Visual Assets:
Inner Grade..……………….4
Color Dispersion.………4
Undertone..…………………4
Total Visual Score…..12 out of 12

__________________________________________________________________________

Lot: 74

Description: 7.71 ct, Fancy Intense Yellow, Cushion, VS2
High Auction Estimation: $19,455 pc

Price Realized: $16,342 pc

Rarity: A small number of similar diamonds enter the market yearly… Check Rarity Here
GIA Report: View

Analysis:
A Fancy Intense Yellow square cushion-cut diamond with a colorless crown. The diamond has a solid Inner-Grade and meets our expectations of a Fancy Intense Yellow. No significant Undertone is visible in the diamond’s color.

Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………3
Total Visual Score…..9 out of 12

__________________________________________________________________________

Lot: 104

Description: 2.42 ct, Fancy Intense Blue, Radiant, VS2
High Auction Estimation: $743,801 pc

Price Realized: $570,662 pc

Rarity: A small number of similar diamonds enter the market yearly… Check Rarity Here 
GIA Report: View

Analysis:
A Fancy Intense Blue Radiant cut with a very large crown and a small table (57%). The crown is completely colorless, which makes the large colorless areas appear very prominent and leaves a small area of color on the face-up view. The Inner-Grade is low and borders on Fancy Blue grade. A noticeable gray undertone is visible in the diamond’s hue.

Visual Assets:
Inner Grade..……………….1
Color Dispersion.………2
Undertone..…………………2
Quality Remark…………Low visual grades overall
Total Visual Score…..5 out of 12

__________________________________________________________________________

Lot: 217

Description: 1.03 ct, Fancy Deep Orangey-Pink, VVS2 
High Auction Estimation: $58,252 pc

Price Realized: $48,933 pc

GIA Report: View

Analysis:
A 1.03 cushion with ~15% Orange and ~75% Pink in the color mix. Most of the crown area is colorless, leaving most of the color under the table. The orange addition in this case gives the stone a warm brown color sensation.

Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Quality Remark…………Warm undertone
Total Visual Score…..8 out of 12

__________________________________________________________________________

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.