Back Arrow Back

Pre-Auction Analysis: September 12th, 2023, Sotheby’s New York

By FCRF Team | 11.09.23
Pre-Auction Analysis: September 12th, 2023, Sotheby’s New York

Important Jewels

Our Sotheby’s’s Important Jewels 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: 63

Description: 3.02 ct, Fancy Intense Yellow, Shield-shaped step-cut, SI1 Clarity. GIA

Analysis: A 3.02 carat fancy intense yellow Shield shaped diamond with a low inner-grade and large colourless areas. Low color dispersion in novelty cut diamonds is quite normal as their shape doesn’t correspond to the ideal facet alignment. 

High Auction Estimation: $16,556 pc

Price Realized:$11,775 pc

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….7 out of 12

__________________________________________________________________________

Lot: 64

Description: 15.89 ct, Fancy Intense Yellow, Cut-cornered rectangular modified, brilliant-cut, VS1 Clarity. Rarity, GIA

Analysis: A large fancy intense yellow radiant cut diamond exhibits a strong Inner-Grade with no significant green or brown undertone affecting its hue. The elongated portion of the crown is colourless, which enhances its long rectangular shape.

High Auction Estimation: $17,621 pc

Price Realized: $22,379 pc

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

__________________________________________________________________________

Lot: 65

Description: 11.28 ct, Fancy Yellow, Cushion-cut, VVS1. Rarity, GIA

Description: 11.22 ct, Fancy Yellow, Cushion-cut, VVS2. Rarity, GIA

Analysis: Two cushion shape diamonds, inscribeed with the GRAFF name,  with a different outline and dimensions. The the 11.22 seems to have a colorless frame around the table and a relative streight outline.

High Auction Estimation: $10,232 pc

Price Realized: $13,547 pc

Visual Assets (11.28 ct diamond):

Inner Grade..……………….3

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

Visual Assets (10.22 ct diamond):

Inner Grade..……………….3

Color Dispersion.………4

Undertone..…………………3

Total Visual Score….10 out of 12

__________________________________________________________________________

Lot: 67

Description: 10.12 ct, Fancy Light Yellow, Oval-shaped, VS2. Rarity, GIA

Analysis: A 10.12-carat fancy light yellow oval with a GIA report dated 2006 exhibits strong blue fluorescence. However, due to the heavy mounting, it is impossible to analyze the three visual characteristics.

High Auction Estimation: $6,916 pc

Price Realized: $6,903 pc

Visual Assets:

Inner Grade..……………….N/A

Color Dispersion.………N/A

Undertone..…………………N/A

Quality Remark: Strong blue fluorescence.

__________________________________________________________________________

Lot: 141

Description: 1.03 ct, Fancy Blue, Pear-shaped, SI2.  Rarity, GIA

Analysis: A 1.03 carat fancy blue pear shape with low inner-grade and dispersion. As seen in the picture there are large colorless areas in the rounded area of the shape. A gray undertone is visible in the hue.

High Auction Estimation: $194,174 pc

Price Realized: $160,292 pc

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………2

Undertone..…………………2

Total Visual Score….6 out of 12

__________________________________________________________________________

Lot: 143

Description: 8.02 ct, Fancy Yellow, Round-cornered rectangular modified brilliant-cut, VS1. Rarity, GIA

Analysis: An 8.02-carat Fancy Yellow cushion shape with a report dated 2009 exhibits prominent colorless areas in the crown, and no substantial green or brown undertone is visible in the hue. The stone’s pavilion is completely covered with yellow gold, preventing us from responsibly analyzing the inner grade.

High Auction Estimation: $8,728 pc

Price Realized: $8,710 pc

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….8 out of 12

__________________________________________________________________________

Lot: 144

Description: 4.09 ct, Fancy Intense Yellow, Cushion-cut, VS2.  Rarity, GIA

Analysis: A 4.09 fancy intense yellow cushion with a large colorless crown around the table. The inner-grade is strong and no substantial undertone is visible in the hue. Report dated 2015.

High Auction Estimation: $14,669 pc

Price Realized: $12,421 pc

Visual Assets:

Inner Grade..………………3.

Color Dispersion.………3

Undertone..…………………3

Total Visual Score….9 out of 12

__________________________________________________________________________

Lot: 145

Description: 1.03 ct, Fancy Purplish Pink, Round Brilliant, SI1. Rarity, GIA

Analysis: A relatively large round brilliant fancy purplish-pink cut diamond with an Argyle logo and report number inscribed on the girdle. According to its rarity report, a round diamond with similar gemological characteristics enters the market once every 1-2 years. The inner grade is very weak, bordering on the fancy light grade, and very few flashes of color are seen on the face-up.

High Auction Estimation: $145,631 pc

Price Realized: $160,292 pc

Visual Assets:

Inner Grade..……………….1

Color Dispersion.………1

Undertone..…………………2

Total Visual Score….4 out of 12

Quality Remark: low visual characteristics

__________________________________________________________________________

Lot: 159

Description: 18.94 ct, Fancy Intense Yellow, Square emerald-cut, VS1. Rarity, GIA

Analysis: An 18.94-carat Emerald cut diamond with a low inner grade and a visible undertone in the hue. Although large colorless areas are visible on the face-up, this is a common feature with fancy color Emerald cut diamonds. The stone has strong blue fluorescence.

High Auction Estimation: $15,839 pc

Price Realized: $13,411 pc

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………2

Undertone..…………………2

Total Visual Score….6 out of 12

Quality Remark: strong blue fluorescence

__________________________________________________________________________

Lot: 167

Description: 6.64 ct, Fancy Vivid Yellow, Oval-shaped, VS2. Rarity, GIA

Analysis: A 6.64-carat fancy vivid yellow oval-shaped diamond with a color origin report (dated 2015). The culet of the stone is missing, and the clarity is likely below the SI2 grade.

High Auction Estimation: $27,108 pc

Price Realized: $33,472 pc

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….8 out of 12

Quality Remark: color only report, unpolished culet.

__________________________________________________________________________

Lot: 193

Description: 1.01 ct, Fancy Deep Pink, Cushion-cut, SI2. Rarity, GIA

Analysis:  A 1.01 fancy deep pink with a brown undertone, SI2 clarity and 73% depth.

High Auction Estimation: $69,306 pc

Price Realized: $62,872 pc

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………2

Undertone..…………………1

Total Visual Score….5 out of 12

Quality Remark:  low undertone, SI2, small face-up

 

__________________________________________________________________________

Lot: 194

Description: 1.02 ct, Fancy Vivid Orange, Pear-shaped, I1. Rarity, GIA

Analysis: A 1.02-carat fancy vivid orange pear-shaped diamond with a color origin report. Due to the sloppy outline of the diamond, it is reasonable to believe that the diamond was not recently polished. The clarity appears to be lower than SI2 and is visible to the naked eye, with a warm undertone. The diamond is polished like a colorless diamond, resulting in low dispersion.

High Auction Estimation: $78,431 pc

Price Realized: $249,020 pc

Visual Assets:

Inner Grade..……………….3

Color Dispersion.………2

Undertone..…………………2

Total Visual Score….7 out of 12

Quality Remark: color only, low clarity, warm undertone.

 

__________________________________________________________________________

Lot: 195

Description: 1.02 ct, Fancy Deep Pink, Emerald-cut, Clarity information is not provided. Rarity, GIA

Analysis: A 1.02 fancy deep pink with a pleasant purple undertone. The diamond has a color origin report probably due to the low clarity, and from the dimensions we have extracted a 76% depth.

High Auction Estimation: $98,039 pc

Price Realized: $186,765 pc

Visual Assets:

Inner Grade..……………….2

Color Dispersion.………2

Undertone..…………………3

Total Visual Score….7 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. 

+

The article has been sent to your email address. Enjoy!

People who read this article, also read:
Research & Insights
The FCRF I.D.U Grading Standard
A fancy color diamond is the most precious stone unearthed in the world. Its endless visual appearances make it the most complex gem to evaluate and price in the luxury space. Today, the vast majority of fancy color diamonds are submitted to the GIA lab to obtain a report confirming their natural origin and gemological […]
Research & Insights
The Integral Role of Storytelling in Fancy Color Diamonds
To illustrate the importance of each element, we have utilized several studies on the subject and created a breakdown with percentages to underline each factor’s significance. The Essence of Brand Prestige: Crafting Legacies – 30%###truncate### The true essence of a luxury brand goes beyond its iconic logos and famous name; it’s deeply embedded in the […]
x close

To continue reading this article

Or

Shopping Cart

You cart is empty

The FCRF App is now available for
Download Button
Continue To Website

The first Market review on Fancy color diamonds

Market Size, retail and customer segments, price evolution, auction insights and much more!

Market Size, retail and customer segments,
price evolution, auction insights
and much more!