Pre-Auction Analysis: April 15th, 2021 Sotheby’s, New York, Magnificent Jewels 

As most of the industry has been prevented from traveling during this challenging period in order to inspect the lots physically, we believe this current analysis is more relevant than ever.                                                 

Our Sotheby’s New York Pre-Auction Analysis focuses on elements that are hidden from the unprofessional eye. We will describe the important visual elements for those who cannot attend the preview and discuss characteristics such as: Undertone, Color Dispersion, and Inner-Grade (UDI; a detailed explanation appears at the bottom of this article). We analyze and grade Fancy Color Diamonds relative to their GIA grade.

We use grades 1, 2, 3, and 4, 1 being the lowest grade. Grade “+” is granted in rare cases and stands for stones with an exceptional characteristic. Stones that receive a minimum total UDI score of 8, without a red remark, pass the industry 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 jewelry brands, collectors and the investment community.

For your convenience, we have added direct links for the GIA reports.

• All images in this article review were taken with an iPhone 12 pro, no filters were applied.
• All auction valuations are per carat and in US Dollars.

Lot #205

5.53 carats, Fancy Vivid Yellow Diamond, Round, VS2 

An extremely small number of similar diamonds enter the market yearly… Check Rarity Here 

And

5.07 carats, Fancy Deep Yellow Diamond, Round, SI1 

A similar diamond enters the market once every… Check Rarity Here 

High catalog estimation: $113,207 per carat

Didn’t reach the minimum

Yellow Fancy Color diamond studs, with a different color grade (Deep and Vivid), are not very common in the high-end jewelry segment. Looking at the visual characteristics such as the greenish undertone in the color and the crystals characteristics in the stone, we can assume these two diamonds were unearthed in the Zimmi area in Sierra Leone. The millimeter measurements are not in close proximity and the overall compatibility is low.     

Visual Assets 

To review the GIA Report of 5.53ct, F.V.Y, RS, VS2 Click here 

Visual Assets 

To review the GIA Report of 5.07ct, F.D.Y,RS, SI1 Click here 

Total Average Score 10 out of 12

Lot #38

3.15 carats, Fancy Vivid Yellow, Marquise, VVS2

High catalog estimation: $20,634 per carat

Didn’t reach the minimum

A Fancy Vivid Yellow Marquise diamond with 70% depth and low color dispersion.

Visual Assets 

Total Visual Score 8 out of 12

To review the GIA Report of 3.15ct, F.V.Y, MQ, VVS2 Click here 

Lot #122

4.58 carats, Fancy Intense Yellow, Round, VS1

An extremely small number of similar diamonds enter the market yearly… Check Rarity Here

High catalog estimation: $10,917 per carat

Price realized: $20,633 pc

A Fancy Intense Yellow Round brilliant with low Inner-Grade and Color Dispersion with no green or brown undertone present in the hue. The symmetry on this round brilliant is “Fair”

Visual Assets 

Total Visual Score 8 out of 12

To review the GIA Report of 4.58ct, F.I.Y, RS, VS1 Click here 

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.