Christie’s New York, Magnificent Jewels, July 29 2020,
Our Christie’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). 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 #125
7.16 carat Fancy Intense Blue, Pear, IF. High catalog estimation: $698,324 per carat
Click here to check the rarity of this stone
Price realized: $538,407 pc
A large Fancy Intense Blue Pear shape diamond with no gray undertone, exhibiting an absolute blue hue. The color dispersion is above average and the Inner-grade is also quite strong.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
3 |
3 |
3 |
Total Visual Score: 9 out of 12
To review the GIA Report Click here
Lot #83
33.65 carat Fancy Intense Yellow, Radiant, VS2. High catalog estimation: $18,573 per carat
Click here to check the rarity of this stone
Didn’t reach the minimum
A very large, Fancy Intense Yellow mix cut Radiant, with average visual characteristics. The two large colorless areas on the crown of the stone are quite prominent and disrupt the overall visual appearance.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
3 |
3 |
3 |
Total Visual Score: 9 out of 12
To review the GIA Report Click here
Lot #163
5.65 carat Fancy Vivid Yellow, Oval, VS1. High catalog estimation: $61,946 per carat
Price realized: $46,460
A vivid Yellow Oval, old-mine style cut. The inner-grade is very high and the undertone exhibits an absolute yellow hue. Due to the old-fashion facet alignment, the color dispersion is very low and the color appears at the two opposite points of the shape. It is important to note that a low color dispersion in an old mine cut stone is quite normal and ‘comes with the territory’.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
4 |
2 |
3 |
Total Visual Score: 9 out of 12
To review the GIA Report Click here
Lot #231
15.13 carat Fancy Green-Yellow, Radiant, SI1. High catalog estimation: $11,896 per carat
Didn’t reach the minimum
According to the ‘Star Burst’ facet alignment of the bottom of the stone, it is reasonable to assume that this diamond was cut and polished during the late 1970’s-/early 1980’s, and as such, has low color dispersion.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
2 |
1 |
2 |
Total Visual Score: 5 out of 12
To review the GIA Report Click here
Lot #29
10.69 carat Fancy Yellow, Radiant, VVS2. High catalog estimation: $11,225 per carat
Click here to check the rarity of this stone
Price realized: $9,939 pc
According to the facet alignment, the table size and the low depth percentages, this stone was re-polished to a Radiant from a Round Brilliant cut. The Inner-grade is low, bordering to a Fancy Yellow and clarity can be most likely improved with minor polishing.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
1 |
3 |
3 |
Total Visual Score: 7 out of 12
To review the GIA Report Click here
Lot #193
2.54 carat Fancy Vivid Yellow, Oval, VVS2.
And
2.50 carat Fancy Vivid Yellow, Oval, VS2.
High catalog estimation: $23,809 per carat
Price realized: $19,841 pc
A matching pair of Vivid Yellow mix cut Oval shape diamonds. Both stones exhibit a strong inner-grade and a warm yellow undertone.
2.54
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
3 |
3 |
1 |
Click here to check the rarity of this stone
To review the GIA Report Click here
2.50
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
3 |
3 |
1 |
Click here to check the rarity of this stone
To review the GIA Report Click here
Total Average Score: 7 out of 12
Lot #93
13.19 carat Fancy Intense Yellow, Old-Mine Brilliant, SI1. High catalog estimation: $6,065 per carat
Price realized: $18,006 pc
This is a large Old-Mine cut, Fancy Intense Yellow Cushion, with uneven color distribution on the GIA report. The SI1 clarity seems to be on the surface and could probably be improved with a simple polishing procedure.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
2 |
1 |
2 |
Total Visual Score: 5 out of 12
To review the GIA Report Click here
Lot #108
1.54 carat Fancy Bluish-Green, Octagonal modified Brilliant cut, SI1. High catalog estimation: $51,948 per carat
Didn’t reach the minimum
An Octagonal-shaped diamond that was probably modified from a classic round brilliant cut in order to reinforce the color. The stone has a strong blue fluorescence.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
4 |
3 |
3 |
Total Visual Score: 10 out of 12
To review the GIA Report Click here
Lot #135
5.05 carat Fancy Intense Yellow, Round, VVS2. High catalog estimation: $13,861 per carat
Click here to check the rarity of this stone
Didn’t reach the minimum
A Round diamond that was modified with odd proportions (very high depth percentages, high crown and small table), in order to concentrate the color in the table area. This facet alignment creates a complete colorless crown and a saturated table area.
Inner Grade |
Color Dispersion |
Undertone |
Quality Remark |
3 |
2 |
3 |
Odd proportions |
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.
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