Two vivid blue pear shapes with similar length and width but different outline, both with high depth percentage (81.9% and 73%). The two stones look smaller relative to their weight and their ratio of 1.4 creates an unconventional look all together. Due to all these abnormalities, It is reasonable to assume that the two stones were originally polished separately as single stones a few decades ago.
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). When we analyse and grade any fancy color diamond it is always done in relation to its GIA description.
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, 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.
Christies, New York Magnificent Jewels, 16 April 2019
Lot #276
3.06 carat Fancy Vivid Blue Pear modified brilliant-cut,VS2
2.61 carat Fancy Vivid Blue Pear modified brilliant-cut,VS2
High catalog estimation: $1,410,934 per carat
Price Realized: $1,189,506 per carat
Click to view GIA Report: 11993126
Click to view GIA Report: 11890077
Two Vivid Blue pear shapes with similar length and width but different outline, both with high depth percentage (81.9% and 73%). The stones look smaller relative to their weight and their ratio of 1.4, wich creates an unconventional look all together. Due to all these abnormalities, it is reasonable to assume that the two stones were originally polished separately as single stones a few decades ago and were mached at a later time.
3.06
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 4 | 3 | 4 |
depth/shape/ratio |
2.61
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
|
3 |
3 |
3 |
depth/shape/ratio |
Total average Visual Score for both stones: 10 out of 12
Lot #252
12.26 carat Fancy Yellow, cut-cornered rectangular modified brilliant-cut, VS1
High catalog estimation: $12,234 per carat
Price Realized: $12,234 per carat
Click to view GIA Report: 11744649
A large Fancy Yellow diamond with a low depth percentage (58%) and ‘extremely thin to medium girdle’. These two characteristics make the stone look larger relative to its weight. Looking at the facet alignment of the stone it is likely to assume the diamond was polished during the 1980’s and as such it exhibits a very low color dispersion.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
|
3 |
1 | 3 |
– |
Total Visual Score: 7 out of 12
Lot #250
6.11 carat Fancy Pink, oval modified brilliant-cut, VVS1, Type IIa
High catalog estimation: $245,499 per carat
Price Realized: $228,314 per carat
Click to view GIA Report: 5141867331
A relatively large Fancy Pink oval accompanied by typical negative visual elements of a Type IIa pink diamond; a warm pink undertone (leaning towards the orangy pink color), visual graning lines and when positioned close to a white diamond light, the pink color slightly fades.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 2 | 3 | 2 | – |
Total Visual Score: 7 out of 12
Lot #240
35.06 carat Fancy Intense Yellow Cushion modified brilliant-cut, SI1
High catalog estimation: $19,965 per carat
Price Realized: $20,108 per carat
Click to view GIA Report: 12019990
A very large Fancy Intense Yellow cushion shape diamond with a solid Inner-Grade and undertone. The Yellow undertone is average.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 3 | 3 | 3 | ✔ |
Total Visual Score: 9 out of 12
Lot #239
37.65 carat Fancy Intense Yellow cut-cornered rectangular mixed-cut, VS1
High catalog estimation: $21,248 per carat
Price Realized: $26,693 per carat
Click to view GIA Report: 11191532
A large Fancy Intense Yellow Radiant cut with a solid Inner-Grade, and average yellow undertone, with no yellow or brown influences. The color dispersion is at the lower end of the grade 3 with relatively many black reflections. According to our rarity data new similar stones enter the market every year.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 3 | 3 | 3 | – |
Total Visual Score: 9 out of 12
Lot #84
7.55 carat Fancy Deep Yellow rectangular-cut, VS1
7.51 carat Fancy Deep Yellow rectangular-cut, VS1
High catalog estimation: $66,401 per carat
Price Realized: Didn’t reach the minimum
A rare match between two Fancy Deep Yellow rectangular Emerald cut diamonds. The Inner-Grade is very strong, as expected from deep Yellow diamonds and without looking at the GIA report one could easily think they are both Vivid Yellow. Both stones have a similar green Undertone and it is reasonable to assume they were both cut out from the same rough or at least came from the same mine.
Click to view GIA Report: 2175558782
Click to view GIA Report: 2175544268
7.55
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 4 | 3 | 2 | Green undertone |
7.51
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 4 | 3 | 2 | Green undertone |
Total average Visual Score: 9 out of 12
Lot #38
4.01 carat Fancy Orangy Pink Pear modified brilliant-cut diamond, VS1
High catalog estimation: $149,625 per carat
Price Realized: Didn’t reach the minimum
Click to view GIA Report: 2181984255
A Fancy Orangy Pink with average characteristics, exhibiting a “warm” color as expected from a combination of orange and pink.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 3 | 3 | 3 | – |
Total Visual Score: 9 out of 12
Sotheby’s, New York Magnificent Jewels April 17th 2019
Lot #139
3.24 carat Fancy Intense Blue cut-cornered square modified brilliant-cut, VVS1
High catalog estimation: $925,926 per carat
Price Realized: $709,876
Click to view GIA Report: 2193852912
A Fancy Intense Blue stone with a low color dispersion and Inner-grade and the hue contains a significant gray undertone. Looking at the facet alignment and from its low depth percentage, we can assume the stone was recut from a round brilliant diamond before it was re-polished into a radiant cut.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 2 | 3 | 2 | – |
Total Visual Score: 7 out of 12
Lot #138
8.88 carat Fancy Intense Yellow,emerald-cut, VS2
High catalog estimation: $19,707 per carat
Price Realized: $21,114 per carat
Click to view GIA Report: 5191638967
A Vivid Yellow square emerald cut diamond with a low color dispersion, color is visible mainly on the four corners of the pavilion reflecting from the face up. The inner grade is solid and undertone is average. The stone’s weight could fetch a premium as it symbolises prosperity and success in the chinese culture.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 3 | 2 | 3 | – |
Total Visual Score: 8 out of 12
Lot #130
1.76 carat Fancy Intense Green, cut-cornered rectangular modified brilliant-cut, SI2
High catalog estimation: $102,272 per carat
Price Realized: Didn’t reach the minimum
Click to view GIA Report: 2195092466
A Fancy Intense Green with a ‘Fair symmetry’ and SI2 clarity. When analyzing the color composition we recognized the presence of yellow and gray.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| 3 | 3 | 2 | SI2/fair symmetry |
Total Visual Score: 8 out of 12
Lot #129
2.21 carat Fancy Brownish Reddish Orange Round cut, I1
High catalog estimation: $67,873 per carat
Price Realized: $53,733 per carat
Click to view GIA Report: 12537060
This 2.21ct. Round brilliant cut contains a very rare color combination, smaller amount of Red and Brown and Orange as the body color. The stone has a large cloud in the center, typically seen in diamonds with a combination of Brown and Orange at the “Deep” grade. Unfortunately, due to the unique combination of characteristic, the standard analysis of the three visual elements is not applicable
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
| N/A | N/A | N/A | I1 |
Total Visual Score: N/A
Lot #63
5.66 carat Fancy Vivid Yellow emerald-cut, VVS1
High catalog estimation: $30,918 per carat
Price Realized: $48,586 per carat
Click to view GIA Report: 6192799745
A Vivid Yellow Emerald cut with a solid Inner-Grade and a good color dispersion for a step cut diamond. The yellow color has no Undertone and exhibits an absolut yellow color.
| Inner-Grade | Color Dispersion | Undertone | Quality Remark |
|
3 |
3 | 4 |
– |
Total Visual Score: 10 out of 12
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.
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