Magnificent Jewels Including the Collection of Rosamund Kwan
Our Christie’s Hong Kong Pre-Auction Analysis focuses on elements that are not always visible to the untrained eye. We discuss characteristics such as Inner-Grade, Color Dispersion, and Undertone – collectively termed IDU. Professionals use the IDU method intuitively when analyzing a Fancy Color Diamond. The acronym we use makes these elements easier to remember.
Members who read this analysis should see it as a valuable supplement to the GIA report. A detailed explanation of the FCRF’s grading methodology can be found at the end of this article. We recommend reviewing it closely to broaden one’s professional vocabulary for describing fancy color diamonds to clients.
Please note that we analyze and grade diamonds under LED lights and relative to their grade on the GIA report.
The Grades
We use grades 1, 2, 3, and 4, with 1 being the lowest grade. Grade “4+” is granted in rare cases and denotes stones with exceptional characteristics. Stones that receive a minimum total IDU score of 9 without a red remark pass the industry premium threshold and can be traded easily. Fancy Color Diamonds that are graded 10 or above (without a quality remark) are usually sought after by high-end jewelers and collectors.
For your convenience, we have added direct links to diamonds’ GIA reports and FCRF rarity stats.
- All images in this analysis were taken with an iPhone 13 Pro; no filters were applied.
- All auction valuations are per-carat and listed in US Dollars.
Disclaimer
This analysis reflects the opinions of the FCRF professional team. It does not constitute a recommendation to buy or not buy a particular diamond. Buyers assume the responsibility of verifying any information with the auction house. At times, mistakes can happen in the visual analysis and report placement. Therefore, one should not rely solely on this analysis for buying purposes.
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Lot: 1812
Description: 2.87 ct, Fancy Intense Yellow, Pear, VS1
High Auction Estimation: $24,497 pc
Price realized: $19,653 pc
Rarity: 49-59 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A Fancy Intense Yellow Pear shape with a rare combination of very high visual assets in all three parameters. The face-up surface corresponds to a much larger carat weight for a pear shape.
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………4
Undertone..…………………4
Total Visual Score….12 out of 12
* We suspect there is a mistake in the stone’s weight. Buyers should double check with the auction house
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Lot: 1814
Description: 3.01 ct, Fancy Vivid Yellow, Heart, VS2
Description: 3.00 ct, Fancy Vivid Yellow, Heart, VS2
High Auction Estimation: $25,557 pc
Price realized: $25,475 pc
Rarity for both: 6-12 diamonds yearly – Share this rarity result – Here
GIA Report 2416022512: View
GIA Report 6382713638: View
Analysis:
Two Fancy Vivid Yellow Heart-shaped diamonds with different width dimensions and a small groove. Both stones share a short and rounded outline. No significant green or brown undertone is visible in the color.
The Inner-Grade is strong, and small colorless patches can be seen on the crown.
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….10 out of 12
Quality remark: Low compatibility
*This lot was previously offered at Sotheby’s Hong Kong on July 19th, 2022 – Read here
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Lot: 1888
Description: 1.01 ct, Fancy Vivid Purplish Pink, Oval, Color report only
High Auction Estimation: $443,643 pc
Didn’t reach the minimum
GIA Report: View
Analysis:
A 1.01 carat Fancy Vivid Purplish Pink with excellent dispersion and a desirable purple undertone. Although the GIA report indicates color and origin only, the diamond’s dimensions reveal a 72% depth which makes the face-up surface area appear small relative to its carat weight.
Several large inclusions are visible to the naked eye on the face-up view. If the stone had been accompanied by a full report, we can assume the clarity would have been an I1. Fluorescence seems to be Medium.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………4
Undertone..…………………4
Total Visual Score….11 out of 12
Quality remark: Low clarity ~I1
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Lot: 1890
Description: 7.92 ct, Fancy Yellow, Pear, VVS1
High Auction Estimation: $15,333 pc
Price realized: $13,235 pc
Rarity: 3-6 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 7.92 Fancy Yellow Pear-shaped diamond with a strong Inner-Grade, several colorless patches, and an insignificant amount of green Undertone. The face-up view of the stone corresponds to a slightly larger carat weight.
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….10 out of 12
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Lot: 1892
Description: 8.47 ct, Fancy Vivid Yellow, Emerald, VS1
High Auction Estimation: $102,572 pc
Price realized: $91,397 pc
Rarity: 6-12 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 8.47 Fancy Vivid Yellow Emerald-cut diamond with a very strong Inner-Grade. The center of the stone is mostly colorless. However, grading dispersion in step-cut diamonds requires a more forgiving approach.
The depth of the stone is 75%, which, in this case, results in a smaller surface area of the face-up relative to its carat size.
Visual Assets:
Inner Grade..……………….4+
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….10+ out of 12
Quality remark: 75%
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Lot: 1893
Description: 5.02 ct, Fancy Intense Orangy Pink, Cushion, Color report only
High Auction Estimation: $305,606 pc
Price realized: $256,251 pc
GIA Report: No report
Analysis:
A 5.02 Fancy Intense Orangy Pink Cushion-cut diamond with a low color dispersion and pleasant soft orange undertone, not having the typical brown color sensation.
Important note to buyers: A GIA report No’ 8768584 was presented to interested buyers during the viewing. However, when we checked the GIA website, we found no report with this number available.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Quality remark: GIA report not found on the GIA website. Low color dispersion.
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Lot: 1942
Description: 12.26 ct, Fancy Intense Yellow, Radiant, VS1
High Auction Estimation: $15,641 pc
Price realized: $19,076 pc
Rarity: 4-7 diamonds yearly – Share this rarity result – Here
GIA Report: View
Analysis:
A 12.26 Fancy Intense Yellow Radiant-cut diamond with a large table, leaving a small crown that is mostly colorless. The Inner-Grade is strong, and no green or brown undertone is present in the hue.
The face-up view appears large relative to the diamond’s carat weight.
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….10 out of 12
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Lot: 1966
Description: 2.62 ct, Fancy Intense Purplish Pink, Oval, I1
High Auction Estimation: $292,775 pc
Didn’t reach the minimum
Rarity: Once every 1-2 years – Share this rarity result – Here
GIA Report: View
Analysis:
Visual Assets:
A 2.62 Fancy Intense Purplish Pink Oval with a very attractive purple undertone, as well as a strong Inner-Grade and color dispersion. The I1 clarity grade is a result of many crystals scattered under the table facet.
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………4
Total Visual Score….11 out of 12
Quality remark: I1
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Lot: 1967
Description: 60.79 ct, Fancy Vivid Yellow, Cushion, VS2
High Auction Estimation: $58,885 pc
Price realized: $43,905 pc
Rarity: Once every 3-4 years – Share this rarity result – Here
GIA Report: View
Analysis:
A 60.79 Fancy Vivid Yellow Cushion-cut diamond. According to the facet alignment, the stone was recut from what used to be an Old Mine Cushion-cut diamond with a lower saturation. Although the saturation was probably improved to a vivid grade, it is only concentrated in a small (57%) table, giving the diamond a disproportionate appearance.
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………1
Undertone..…………………3
Total Visual Score….8 out of 12
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General
We use 1, 2, 3, 4, and 4+ to grade the three visual elements that GIA is silent about, although 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 common).
Grade 3 full-bodied color (above average).
Grade 4 very strong saturation.
Grade 4+ applies to 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 that is 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 as 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 is the result of cutter proficiency.
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