Pre-Auction Analysis: October 7th 2020, Sotheby’s Hong Kong, Magnificent Jewels

As most of the industry has been prevented from flying during this special period and inspect the lots physically, we believe this current analysis is even more relevant than ever.                                                 

Our Sotheby’s Hong-Kong 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). When we analyze and grade any Fancy Color Diamond it is always done in relation to its 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, are considered to be “Gems” and are generally 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 11pro, no filters were applied.
• All auction valuations are per carat and in US Dollars.

Lot #1753

1.95 carat Fancy Intense Blue, Round, VVS1

And

1.63 carat Fancy Intense Blue, Round, VS1

High catalog estimation: $1,261,565 per carat

Didn’t reach the minimum

The color characteristics for this “pair” of rounds are quite similar, but the cut and proportions are very different, a  fact that impacts the premium this item should have received as a matching pair I.e. a very different table size (58% and 62%), depth and different crown angles.

1.95 

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To review the GIA Report Click here

1.63

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To review the GIA Report Click here 

Total Average Score: 9.5 out of 12

Lot #1756

4.84 carat, Fancy Vivid Blue, Pear, IF. High catalog estimation: $1,732,813 per carat

Withdrawn from auction

Click here to check the rarity of this stone

A rare, Blue Vivid pear shape, with poor dispersion as a result of a traditional brilliant cut suitable for colorless diamonds. The stone has a pleasant Undertone, with very little grey undertone. The Inner-Grade is above average.

Total Visual Score: 9 out of 12

To review the GIA Report Click here 

Lot #1752

5.22 carat Fancy Intense Blue, Radiant, IF. Mount signed Cartier. High catalog estimation: $741,606 per carat

Price Realized: $856,736

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An Intense Blue diamond with very low Inner-Grade, bordered with a Fancy Blue. The color dispersion is above average and the Undertone has very little grey influence.

Total Visual Score: 7 out of 12

To review the GIA Report Click here

Lot #1751

3.64 carat Fancy Pink, Round, IF. High catalog estimation: $248,130 per carat

Didn’t reach the minimum

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Pink Fancy Color Diamonds are rarely seen in a round brilliant cut. This diamond was polished in an unconventional way to reinforce the color in the center of the diamond (high crown and high dept – 63%). The Undertone leans towards a warm Pink and the Inner-Grade is weak in comparison to a modified fancy shape and average for a round fancy color. 

Total Visual Score: 6 out of 12

To review the GIA Report Click here

Lot #1750

8.88 carat Fancy Vivid Yellow, Oval, VS2. High catalog estimation: $87,185 per carat

Price Realized: $122, 101 pc

Click here to check the rarity of this stone

Highly saturated Vivid Yellow Oval diamond, with a symbolic, thought after carat weight. Although the color is outstanding, the fact that the facet alignment is not ideal to concentrate color, creates a large colorless area in the center of the diamond, as seen clearly in the photo. 

Total Visual Score:  out of 12

To review the GIA Report Click here

Lot #1745

2.08 carat Fancy Vivid Purplish Pink, Oval, SI2. High catalog estimation: $930,521 per carat

Didn’t reach the minimum

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A Fancy Vivid Purplish-Pink, with a relatively low clarity. The Undertone is quite pleasant, however, there are large visible colorless areas on the crown.

Total Visual Score: 10 out of 12

To review the GIA Report Click here 

Lot #1722

18.68 carat Fancy Light Purplish Pink, Radiant, SI2. High catalog estimation: $117,421 per carat

Didn’t reach the minimum

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A very large Purplish-Pink, with low clarity and average visible characteristics.

Total Visual Score: 8 out of 12

To review the GIA Report Click here

Lot #1721

 23.54 carat Fancy Vivid Yellow, Pear, VS1. High catalog estimation: $38,367 per carat

Didn’t reach the minimum

Click here to check the rarity of this stone

A relatively large, Fancy Vivid Yellow Pear-shaped diamond. The diamond has an odd shape, mainly due to the fact that the outline on the bottom of the shape is quite flat. The undertone leans towards a warm Yellow.

Total Visual Score: 8 out of 12

To review the GIA Report Click here 

Lot #1717

17.64 carat Fancy Yellow, Radiant, IF.

And

17.54 carat Fancy Yellow, Radiant, IF.

High catalog estimation: $15,404 per carat

Price Realized: $14,778 pc

Two very large Fancy Yellow Radiant diamonds, with matching gemological characteristics. However, one of them has 2 visible colorless areas, seen from the table, which lowers the compatibility as clearly seen in the image.

17.64

To review the GIA Report Click here

Click here to check the rarity of this stone

17.54

To review the GIA Report Click here

Click here to check the rarity of this stone

Total Average Score: 9.5 out of 12

Lot #1716

10.09 carat Fancy Yellow, Marquise, SI2. High catalog estimation: $20,460 per carat

Price Realized: $19,335 pc

Large Fancy Yellow marquise diamonds are very rare in the market and are quite a unique item. This diamond however, suffers from a low color dispersion, due to a traditional colorless brilliant cut, and has a visible SI2 clarity.

Total Visual Score: 9 out of 12

To review the GIA Report Click here 

Lot #1618

7.33 carat, Light Pink, Pear, VS2. High catalog estimation: $66,891 per carat

Price Realized: $64,324

Click here to check the rarity of this stone

This Light Pink Pear-shaped diamond was polished in a traditional pear brilliant cut, which created a large colorless center. The Undertone appears average.

Total Visual Score: 8 out of 12

To review the GIA Report Click here 

Lot #1616

5.01 carat Fancy Vivid Yellow, Cushion, SI2. High catalog estimation: $20,603 per carat

Price Realized: $21,093 pc

Click here to check the rarity of this stone

A 5-carat Vivid Yellow Cushion cut diamond, with exceptional visual characteristics. However, it has a SI2 clarity grade, due to large, visible inclusions in the center of the stone. 

Total Visual Score: 12 out of 12

To review the GIA Report Click here 

Lot #1615

1.01 carat Fancy Intense Green, Radiant, VS2. High catalog estimation: $102,200 per carat

Price Realized: $80,486 pc

A Fancy Intense Green Radiant diamond, with average visual characteristics.

Total Visual Score:  out of 12

To review the GIA Report Click here 

General

We use 1, 2, 3, 4, and 4+ to grade the three visual elements that GIA is silent about, however 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 abounded).

Grade 3 full-bodied color (above average).

Grade 4 very strong saturation.

Grade 4+ applies for 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 and will be 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 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 has only to do with cutter proficiency.