Pre-Auction Analysis: April 2nd 2019, Sotheby’s Hong Kong, Magnificent Jewels and Jadeite

Our Pre-Auction Analysis focuses on elements that are hidden from the unprofessional eye. As always, we will describe the important visual elements for those who cannot attend the preview. We will discuss characteristics such as Undertone, Color Dispersion, and Inner-Grade (UDI; a detailed explanation appears at the bottom of this article) the total UDI visual grade is mention under each chart.

We use grades 1, 2, 3, and 4, 1 being the lowest grade. Grade 4+ is granted in rare cases and stands for stones with an exceptional characteristic. Stones that receive a minimum total UDI score of 8, with a  ✔ , are mostly suitable for high-end jewelry, 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 10, no filters were applied.
• All auction valuations are per carat and in US Dollars.

Sotheby’s, Hong Kong Magnificent Jewels and Jadeite, April 2nd, 2019

Lot #1798

3.32 carat Fancy Vivid Blue cut-cornered rectangular step-cut, IF

High catalog estimation: $2,302,409 per carat

Price Realized: Didn’t reach the minimum 

According to the FCRF rarity data, vivid blue Emerald cut diamonds in this specific size and  clarity category enter the market once every 3-4 years. This 3.32 blue diamond has a very high Inner-Grade and an absolute blue undertone with no traces of gray. Although the centre area of the stone is less saturated, color dispersion is quite high for a step cut diamond.

Total Visual Score: 12 out of 12

To review the GIA Report Click here (6193579353)

Lot #1788

2.56 carat Fancy Vivid Blue, Radiant cut, I1 clarity.

High catalog estimation: $1,393,437 per carat

Price Realized: Didn’t reach the minimum 

This stone has two triangle colorless areas on each side. This geometrical appearance is typically seen in Emerald cut diamonds that were polished into a Radiant cut. This is usually done in order to achieve a stronger inner-grade or make inclusions less visible. Low clarity in blue diamonds is rarely seen.

Total Visual Score: 9 out of 12

To review the GIA Report Click here (5192617192)

Lot #1784

3.05 carat Fancy Intense Green, round-cornered square modified brilliant-cut SI2

High catalog estimation: $271,508 per carat

Price Realized: $248,219

Looking closely on this green diamond a few patches of green color are visible. Green patches actually appear long after the formation of the diamond due to a long exposure to natural radiation. These patches reflect on the whole diamond and color the stone  green. The SI2 is not very visible, however, once you recollect the location of the inclusions, they can be seen without a loupe. The undertone of the diamond does not correspond to what most people expect from a Green Diamond and hence, receives a low undertone grade. The inner grade is above the average and color dispersion is high.  

Total Visual Score: 9 out of 12

To review the GIA Report Click here (1149231777)

Lot #1783

1.21 carat Fancy Vivid Green-Blue, cut-cornered rectangular modified brilliant-cut SI1

High catalog estimation: $737,024 per carat

Price Realized: Didn’t reach the minimum 

A very rare combination of size, color and saturation. The inner grade, undertone and color dispersion receive the highest possible grade and create a unique visual experience. The diamond has a strong-blue fluorescence, but since it does not contradict with the body color of the diamond, there should not be any negative effect. The 74 depth percentage creates a visual effect of a  smaller stone in relation to its weight.

Total Visual Score: 12+ out of 12

To review the GIA Report Click here (2155795723)

Lot #1781

1.16 carat Fancy Vivid Purplish Pink, cut-cornered rectangular mixed-cut I2

High catalog estimation: $274,568 per carat

Price Realized: Didn’t reach the minimum 

A vivid purplish pink with an extraordinary pink saturation. An Argyle number is inscribed on the girdle, however, the stone does not appear in any of the Argyle tender catalogues from recent years. The white feathers and crystals that decorate the inside of the diamond are visible to the naked eye.

Total Visual Score: 12 out of 12  

To review the GIA Report Click here (1152827543)

Lot #1780

5.20 carat Fancy Grey-Blue, emerald-cut VS1

High catalog estimation: $68,600 per carat

Price Realized: $245,675

Fancy color diamonds that have ‘Gray’ in their color composition, will exhibit a strong Inner-Grade such in this Emerald cut. The color dispersion is average and the undertone meets the GIA description.  

Total Visual Score: 10 out of 12

To review the GIA Report Click here (5313738431)

Lot #1714

20.41 carat Fancy Vivid Yellow, cut-cornered square modified brilliant-cut VS2

High catalog estimation: $56,178 per carat

Price Realized: Didn’t reach the minimum 

A Vivid Yellow with a good color dispersion an average Inner-Grade and undertone.

Total Visual Score: 10 out of 12

To review the GIA Report Click here (2165680997)

Lot #1712

2.15 carat Fancy Vivid Yellow, brilliant-cut VVS2

2.08 carat Fancy Vivid Yellow, brilliant-cut VVS1

High catalog estimation: $39,153 per carat

Price Realized: $45,234

Two round diamonds with abnormal proportions, typically seen in Fancy Color round diamonds in order to reinforce saturation. Depth percentage in both stones is 63 and 64 and a 66% table. This combination creates a ring of color in the table area and a colorless crown, which lowers the general aesthetic appearance of the stone.

2.15

2.08

Total Average Visual Score: 7.5 out of 12

To review the GIA Report Click here (2185642046, 1182642049)

Lot #1709

6.98 carat Fancy Pink-Brown, pear-shaped SI1

6.66 carat Fancy Pink-Brown, pear-shaped Internally Flawless

High catalog estimation: $56,041 per carat

Price Realized: $51,014

Although this color combination is not located at the top of the value scale, it is quite rare to find a large pair of pear shapes such as this one. The visual elements are average and the SI1 clarity, is visual to the naked eye.  

6.98

6.66

Total Average Visual Score: 8 out of 12

To review the GIA Report Click here (1172028343, 2175018061 )

Lot #1708

5.01 carat Fancy Pink-Purple, pear-shaped I2

High catalog estimation: $81,373 per carat

Price Realized: Didn’t reach the minimum 

A large Purple pear shape cut diamond with a pink modifier. The Inner-Grade is strong and the undertone meets our expectations from a diamond with purple body color. The inclusion is visible to the naked eye.

Total Visual Score: 11 out of 12

To review the GIA Report Click here (6302204380)

Lot #1707

2.05 carat Fancy Brown-Orange pear-shaped, VS2

2.02 carat Fancy Intense Yellow pear-shaped, VS2

2.02 carat Fancy Brownish Purple-Pink pear-shaped I1

2.01 carat Fancy Intense Orange-Yellow pear-shaped VS1

High catalog estimation: $31,456 per carat

Price Realized: $25,590

A combination of 4 pear shapes with warm colors.

2.05

2.02 Fancy Intense Yellow

2.02 Fancy Brownish Purple-Pink

2.01

Total Average Visual Score: 9.5 out of 12

To review the GIA Report Click here (7218102117, 2145659474, 1218701853, 6167925919)

Lot #1706

3.31 carat Fancy Yellowish Green, modified rectangular brilliant-cut, VS2

High catalog estimation: $46,187 per carat

Price Realized: Didn’t reach the minimum 

A green diamond with a yellow modifier with a strong Inner-Grade. Average color dispersion and undertone.

Total Visual Score: 10 out of 12

To review the GIA Report Click here (7208523649)

General

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