Pre-Auction Analysis: July 10th 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 #1807

4.49 carat Fancy Vivid Pink, Heart, IF. High catalog estimation: $1,954,075 per carat

Price realized: $1,810,427 pc

A 4 carat Fancy Vivid Pink is considered to be very rare, regardless of its shape and clarity. Although the color characteristics are very good in this case, the outline of a heart shape diamond has a symbolic role. Heart shapes that don’t exhibit a classic shape, such as this one, would be considered as, ‘less attractive’.The outline of this heart shape is not traditional as the two “shoulders” are too far apart from each other, probably due to the initial shape of the rough, or other clarity or weight constraints that needed to be addressed during the polishing process.

Market Prevalence: A similar diamond enters the market once every 8 to 12 years

Total Visual Score: 10 out of 12

To review the GIA Report Click here

Lot #1806

5.04 carat Fancy Vivid Blue, Heart, VS2. High catalog estimation: $1,920,036 per carat

Price realized: $2,094,003 pc

A very rare Blue diamond with a strong Inner-grade and high color Distribution. The Undertone has no gray and meets the color description nickname used by the industry, “Ink Blue”. Similar to the previous lot (#1807), this stone doesn’t have an ideal outline of a classic heart shape, which may affect its marketability. In this case, the groove (cleavage) between the two “shoulders” is not deep enough and gives more of a feeling of a triangular diamond shape and impacts its overall esthetic.

Market Prevalence: A similar diamond enters the market once every 8 to 12 years

Total Visual Score: 11 out of 12

To review the GIA Report Click here 

Lot #1805

8.88 carat Fancy Vivid Yellow, Radiant, IF. High catalog estimation: $34,872 per carat

Price realized: $47,220 pc

A Vivid Yellow Radiant cut with a desired carat weight. The number 8 is considered to be a lucky number in Chinese culture, a virtue that usually attracts Asian buyers. However, the size of the stone in terms of mm, reflects a diamond in the vicinity of 7.50 carats. In addition, the combination of the high crown, a very small table and the large, dark colorless areas in the face-up view, disrupts the general esthetic of the stone.  

Market Prevalence:  A mere 3 to 5 similar diamonds enter the market yearly

Total Visual Score:  8 out of 12

To review the GIA Report Click here 

Lot #1699

30.07 carat Fancy Intense Yellow, Radiant, VS1. High catalog estimation: $27,890 per carat

Price realized: $23,921 pc

A very large, Fancy Intense Yellow Cushion, with an uncommonly thick girdle (as seen in the video). The Inner-Grade is average for an Intense and the two large, black colorless areas on the crown are quite noticeable.    

Market Prevalence: A mere 1 to 3 similar diamonds enter the market yearly

Total Visual Score:  8 out of 12

To review the GIA Report Click here 

Lot #1697

4.05 carat Fancy Intense Purplish-Pink, Marquise, SI2. High catalog estimation: $254,867 per carat

Price realized: $387,882 pc

A Fancy Intense Purplish Pink, with exceptional visual characteristics. The Intense Inner-Grade borders with the “Vivid” grade and no brown undertone is visible in the color mix. The color dispersion is quite high, although the stone is polished according to colorless diamonds parameters. The SI2 clarity is peripheral, however with many crystals and indented naturals.

Total Visual Score:  11 out of 12

To review the GIA Report Click here 

Lot #1658

2.59 carat Fancy Deep Purple Pink, Radiant, VS2. VAN CLEEF & ARPELS. High catalog estimation: $323,811 per carat

Didn’t reach the minimum

A unique color combination, especially because the grade Deep is relatively uncommon in pink diamonds above one carat. The significant purple presence, in combination with the Deep grade, creates a “warm” undertone and may not achieve a premium. Although the stone has a Van Cleef mounting, we strongly recommend authenticating the ring before granting a brand premium.    

Market Prevalence: A similar diamond enters the market once every 2 to 3 years

Total Visual Score:  8 out of 12

To review the GIA Report Click here 

Lot #1655

1.01 carat Fancy Intense Blue, Heart, I1. 

1.01 carat Fancy Orangy Pink, Heart, VS2. 

High catalog estimation: $127,749 per carat

Price realized: $131,740 pc

A Toi e Moi ring, featuring two Heart-shaped diamonds with high visual characteristics. This Fancy Intense Blue is graded as I1 and has a Fair symmetry. 1.01 Blue 

To review the GIA Report Click here

Market Prevalence for a single stone: A similar diamond enters the market once every 8 to 12 years

1.01 Orangy Pink

To review the GIA Report Click here 

Total Average Score:  11 out of 12

Lot #1654

1.02 carat Fancy Purplish Pink, Heart, SI1. 

1.01 carat Fancy Purplish Pink, Heart, SI1. 

High catalog estimation: $108,051 per carat

Price realized: $91,368 pc

Two Heart-shaped diamonds with a matching clarity grade of SI1, and a low undertone grade

1.02

To review the GIA Report Click here 

Market Prevalence for a single stone: A mere 4 to 8 similar diamonds enter the market yearly

1.01

To review the GIA Report Click here 

Market Prevalence for a single stone: A mere 4 to 8 similar diamonds enter the market yearly

Total Average Score: 8 out of 12

Lot #1653

1.07 carat Fancy Intense Pink, Radiant. High catalog estimation: $217,054 per carat

Didn’t reach the minimum

An Intense Pink with a “warm” orange undertone.The GIA color-only report was not renewed and is dated 2004. In most cases this report is issued when the diamond has strong blue fluorescence, low clarity grade or both.    

Market Prevalence:  A mere 4 to 7 similar diamonds enter the market yearly

Total Visual Score: 7 out of 12

To review the GIA Report Click here 

Lot #1631

8.02 carat Fancy Intense Yellow, Cushion, VS2. High catalog estimation: $14,479 per carat

Didn’t reach the minimum

An 8 carat Fancy Intense Yellow Cushion-cut diamond, with a low undertone grade and average visual characteristics.
 

Market Prevalence:  A mere 10 to 13 similar diamonds enter the market yearly

Total Visual Score:  8 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.