The World of Heidi Horten: Magnificent Jewels Part I
Pre-Auction Analysis: May 10th, 2023, Christies Geneva, The World of Heidi Horten: Magnificent Jewels Part I
Heidi Horten’s jewelry collection, is a true testament to her diversed taste and love for diamonds of all colors and qualities. Her affinity for fancy color diamonds is evident, particularly her fascination with the warm undertone pink color diamonds and jewelry with heart-shapes. From impressive monochromatic sets like the orangey pink set, to the stunning yellow pear-shaped ensemble, she was unafraid to explore diamonds in all their splendor. It is clear that she was a true collector at heart, unconcerned to appreciate the diamond’s beauty of different qualities.
However, while Heidi Horten’s jewellery collection is undoubtedly impressive, it is important to remember the controversy source of her late husband’s wealth. Helmut Horten, a German entrepreneur, made his fortune through a chain of department stores. However, it has been widely reported that his initial wealth was built upon buying houses of Jews who were taken from their homes to concentration camps during World War II. This raises a moral question about the Horten family’s participation as buyers in these circumstances, and their contribution to the accumulation of wealth through such means. While the collection itself is remarkable, it is important to remember the ethical concerns surrounding its acquisition.
Our Christie’s Geneva 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: 4
Description: 1.79 ct, Fancy Intense Blue, Marquise, VVS1
Analysis:
A Fancy Intense blue marquise with a low depth percentage creates a large face-up appearance relative to its weight. The blue color is inconsistently scattered throughout the face-up view, with a subtle gray undertones. The inner-grade, , is average.
High Auction Estimation: $ 449,710 pc
Price realized: $512,558 pc
GIA Report: View
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….7 out of 12
Quality remark: low dispersion
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Lot: 12
Description: 13.44 ct, Fancy Intense Yellow, Heart, VS1
Analysis:
An elongated 13.44-carat fancy Intense yellow heart-shaped diamond with a ratio of 1:1.10. The traditional brilliant cut facet alignment indicates that it was manufactured in the middle of the last century, before the modified cut was introduced. Most of the color is concentrated at the point of the shape, leaving very little color visible in most of the face-up view. However, the heart-shaped face-up appears larger relative to its weight.
High Auction Estimation: $ 22,460 pc
Price realized: $21,116 pc
Rarity: 1-2 diamonds yearly – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.……….1
Undertone..…………………3
Total Visual Score….7 out of 12
Quality remark: low color dispersion
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Lot: 14
Description: 10.22 ct, Fancy Intense Yellow-Green, Heart, VS2
Analysis:
A rare size for a Fancy Intense yellow-green diamond, with a below-average inner-grade and a tarnished green undertone. According to the GIA report, patches of color are present in the diamond, although they are not visible to the naked eye, which is a common characteristic in natural green diamonds.
High Auction Estimation: $ 153,087 pc
Price realized: $178,400 pc
Rarity: Once every 25 years or more – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….8 out of 12
Quality remark: low undertone
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Lot: 39
Description: 30.19 ct, Fancy Yellow, Round, VS2
Analysis:
A Fancy Yellow oval-cut diamond with a large face-up appearance relative to its weight. The oval has a low length-to-width ratio of 1:1.2 with a rounded outline. The inner-grade and undertone specified below should be taken with reservation as the diamond is completely covered with gold.
High Auction Estimation: $ 11,850 pc
Price realized: $15,031 pc
Rarity: Once every 8-12 years – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….8 out of 12
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Lot: 43
Description: 6.99 ct, Fancy Intense Pink, Emerald, VVS1
Analysis:
A 6.99-carat fancy Intense pink Emerald-cut diamond, polished without any modification to enhance the face-up color, resulting in most of the table area appearing colorless. The diamond has a warm undertone but does not give off a brown color sensation. The inner-grade is strong.
High Auction Estimation: $ 102,970 pc
Price realized: $1,472,132 pc
Rarity: Once every 9-10 years – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Quality remark: low dispersion
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Lot: 52
Description: 3.06 ct, Fancy Intense Blue, Square, SI2
Analysis:
A 3.06-carat Fancy Intense Blue square emerald-cut diamond, polished without any modification to enhance its face-up color. The SI2 clarity results from a large feather on the pavilion, as seen in the second image. The inner-grade is very strong, and a typical light gray undertone is present in the hue.
High Auction Estimation: $ 840,350 pc
Price realized: $906,984 pc
Rarity: Once every 8-12 years – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….10 out of 12
Quality remark: SI2 clarity
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Lot: 54
Description: 20.06 ct, Fancy Pink, Pear, VVS2
Analysis:
A 20.06-carat Fancy Pink pear-shaped diamond with an unconventional outline of the rounded area. The undertone leans towards the colder spectrum, and the inner-grade is not strong. The orange fluorescence is a rare occurrence in pink fancy color diamonds and is often associated with diamonds unearthed from the Golconda mine in India.
High Auction Estimation: $ 351,126 pc
Price realized: $240,223 pc
Rarity: Once every 25 years or more – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
Quality remark: odd outline
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Lot: 58
Description: 27 diamond with 26 GIA reports on 2.55 to 0.55 carats, graded as Fancy Orangy Pink from Internally Flawless to SI2 clarity.
Analysis:
A collection of fancy orangy-pink diamonds in various sizes, shapes, and clarities. The undertones and inner-grades are not consistent, and the diamond layout appears to be a random collection of diamonds with the same color grade.
Total High Auction Estimation: $ 504,796 pc
Price realized: $1,049,032 Total
Rarity: N/A
GIA Report: View
Visual Assets:
Inner Grade..……………….N/A
Color Dispersion.………N/A
Undertone..…………………N/A
Total Visual Score….N/A out of 12
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Lot: 59
Description: 46 diamonds with 44 GIA reports weighing 64.26 carat dated, 2007-2019: from 4.38ct to 0.81ct. All Fancy Orangy Pink, natural colour. IF to SI2 clarity
Analysis:
A collection of fancy orangy-pink diamonds in various sizes, shapes, and clarities, with one diamond (5.03 carats, GIA report number 5222912925) graded as treated. The undertones and inner-grades are not consistent, and the diamond layout appears to be a random collection of stones mounted in one necklace.
Total High Auction Estimation: $ 78,815 total
Didn’t reach the minimum
Rarity: N/A
GIA Report: View
Visual Assets:
Inner Grade..……………….N/A
Color Dispersion.………N/A
Undertone..…………………N/A
Total Visual Score….N/A out of 12
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Lot: 60
Description: 10.42 ct, Fancy Intense Pinkish Orange, Pear, VS2
Analysis:
A 10.42-carat Fancy Intense Pinkish Orange pear-shaped diamond. Orange diamonds with a pink modifier are extremely rare in nature and receive a significant premium when they exhibit a soft peach undertone. The undertone in this case leans towards a warm orange that may change to a colder one according to the light it is exposed to.
High Auction Estimation: $ 289,700 pc
Price realized: $200,714 pc
Rarity: N/A
GIA Report: View
Visual Assets:
Inner Grade..……………….4
Color Dispersion.………3
Undertone..…………………2
Total Visual Score….9 out of 12
Quality Remark: Low undertone
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Lot: 61
Description: 35.89 ct, Fancy Pink, Pear, IF
Analysis:
An extremely large fancy pink pear-shaped diamond with low color dispersion and a cold pink undertone. The length-to-width ratio is 1:1.89, which is unconventional for a pear shape. The inner-grade is very low and may be mistaken for a fancy light when placed under diamond light (as most Type IIa diamonds do).
High Auction Estimation: $ 420,546 pc
Didn’t reach the minimum
Rarity: Once every 25 years or more – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..………………..1
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….7 out of 12
Quality Remark: Low Inner-Grade
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Lot: 65
Description: A Pair of earrings with four Fancy Light Pink and Fancy Light Orangy Pink Pear shape diamonds weighing 11.33 ct, 10.94, 2.83 and 2.54 ct.
Analysis:
A matching pair of fancy light pink pear-shaped diamonds with similar dimensions and GIA reports dated 2012 and 2014. The inner-grade is low, and the undertone leans towards the cold spectrum of the pink color. The two pear-shaped diamonds at the top do not share the same color grade.
High Auction Estimation: $ 84,976 pc
Price realized: $102,764 pc
Visual Assets 11.33:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
Visual Assets 10.94:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
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Lot: 66
Description: 12.27 ct, Fancy Pink, Heart, VVS1
Analysis:
A 12.27-carat fancy pink heart-shaped diamond with a very low inner-grade and a pleasant undertone and well-dispersed color. The diamond crystal has a soft haziness that may affect the overall sparkle, and the remark on the bottom of the GIA report “clarity is based on internal graining” supports this observation, a feature that is popular in most Type IIa diamonds. The face-up view of the diamond appears much larger in relation to its weight.
High Auction Estimation: $ 246,138 pc
Price realized: $237,020 pc
Rarity: Once every 4-5 years – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..………………..1
Color Dispersion.………4
Undertone..…………………3
Total Visual Score….8 out of 12
Quality remark: low inner-grade and a visible haziness in the crystal
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Lot: 74
Description: 32.32 ct, Fancy Yellow, Cushion, VS2
Analysis:
A large cushion-cut diamond that was likely manufactured in the middle of the last century has extremely low color dispersion, only visible when tilted. Despite this, the inner-grade is high for a fancy yellow diamond. The 77% depth of the cushion cut makes the face-up view appear smaller relative to its weight.
High Auction Estimation: $ 17,239 pc
Price realized: $14,887 pc
Rarity: 1-2 diamonds yearly – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.…….…1
Undertone..…………………3
Total Visual Score….7 out of 12
Quality remark: low color dispersion, appears small relative to weight
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Lot: 75
Description: 20.92 ct, Fancy Vivid Yellow, Cushion, VS1
Analysis:
A 20.92 carat fancy vivid yellow cushion cut diamond with a classic facet alignment, and indication to the early period it was manufactured. The color dispersion is low with many colorless areas. The inner-grade is very strong and no green or brown undertone is visible in the hue. The face up view appears larger in relation to its weight.
High Auction Estimation: $ 48,127 pc
Price realized: $93,357 pc
Rarity: 1-3 diamonds yearly – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….4
Color Dispersion.…….…1
Undertone..…………………4
Total Visual Score….9 out of 12
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Lot: 88
A broach with 4 fancy color diamonds.
Description: 5.14 ct, Fancy Intense Orange, Pear, I1 GIA
Description: 5.00 ct, Fancy Intense Purple-Pink, Heart, SI2 GIA
Description: 4.26 ct, Fancy Blue, Marquise, VS1 GIA
Description: 3.82 ct, Fancy Intense Yellow, Marquise, SI1 GIA
Analysis:
The 5.14 carat Fancy Intense Orange Pear Shape has an I1 clarity resulting from two large feathers in the rounded area. The undertone is unusual for an orange and displays a peachy color sensation under certain light sources.
The 5.00 carat intense Purple-Pink portrait heart shape has an SI2 clarity and fair symmetry. The purple modifier grants a desirable undertone. Low dispersion is inherent for any portrait diamond.
The 4.26 carat fancy blue marquise has a classic facet alignment with no modification to concentrate color on the face-up view, and thus, color is concentrated at the two points shape, leaving most of the face-up colorless. No gray undertone is in the color.
The 3.82 carat fancy intense yellow has an open culet and was polished in a very old manner, creating low dispersion. The SI1 clarity is due to a feather on the crown, near one of the points. A soft green undertone is present in the hue.
Total High Auction Estimation: $$7,183,58 Total
Price realized: $5,142,636 Total
Rarity: N/A
Visual Assets for the 5.14ct:
Inner Grade..……………….2
Color Dispersion.………3
Undertone..…………………3
Total Visual Score….8 out of 12
Visual Assets for the 5.00ct:
Inner Grade..……………….3
Color Dispersion.….……1
Undertone..…………………4
Total Visual Score….8 out of 12
Visual Assets for the 4.26ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………4
Total Visual Score….9 out of 12
Visual Assets for the 3.82ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………4
Total Visual Score….9 out of 12
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Lot: 89
A Harry Winston Fancy intense yellow, fancy yellow and fancy light yellow diamond necklace with 18 center diamonds of various shapes and cuts weighing 18.37 ct, 17.20 ct, 15.73 ct, 15.63 ct and 14.10 ct.
18.37 ct GIA
17.20 ct GIA
15.73 ct GIA
15.63 ct GIA
14.10 ct GIA
14 GIA reports, 2002-2023: oval and oval modified brilliant-cut, 7.39 to 1.23 carats, Fancy Yellow, natural colour, VVS1 to VS2 clarity
Price realized: $1,815,897 Total
Rarity: N/A
Analysis:
An ensemble of large yellow fancy color diamonds in various saturations and clarities is displayed. Color dispersion on most diamonds is low, and the inner-grade is different, creating an inconsistent appearance for this arrangement of diamonds.
Quality Remark: A large amount of low quality diamonds
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Lot: 90
Description: A bracelet comprised of 7 oval diamonds, signed Van Cleef & Arpels in the following weights: 12.41, 6.57, 6.56, 6.05, 5.54, 4.85 and 4.83. All are natural intense yellow VVS and VS clarity.
*Although the bracelet and the necklace have an identical desgin, they are signed by different jewelry brands, according to the auction catalog.
Analysis:
The seven Fancy Intense Yellow ovals are graded as such and feature an old-fashioned cutting style, likely originating from the latter half of the previous century. All the diamonds were cut identically, exhibiting very low color dispersion and high inner-grade.
High Auction Estimation: $ 15,620 pc
Price realized: $33,306 pc
Rarity: N/A
7 GIA Reports: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.…….…1
Undertone..…………………3
Total Visual Score….7 out of 12
Quality Remark: low dispersion on all diamonds
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Lot: 91
Description: A pair of earrings with four Fancy intense yellow Pear cut diamonds weighing 25.42 ct, 25.31 ct, 3.81 ct and 3.50 ct. all Fancy Intense Yellow.
Analysis:
Two pear-shaped fancy intense yellow diamonds with no modification to concentrate color on the face-up view, resulting in low color dispersion. The measurements and inner grade of the two diamonds are not compatible. The 25.42ct diamond has a low inner grade, while the 25.31ct diamond has a strong inner grade and an average undertone
Total High Auction Estimation: $ 34,495 pc
Price realized: $41,818 pc
Rarity: N/A
Visual Assets 25.42 ct:
Inner Grade..……………….2
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….7 out of 12
Visual Assets 25.31 ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Visual Assets 3.81 ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Visual Assets 3.50 ct:
Inner Grade..……………….3
Color Dispersion.………2
Undertone..…………………3
Total Visual Score….8 out of 12
Quality Remark: Low color dispersion on all four diamonds
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Lot: 92
Description: 34.01 ct, Fancy Intense Yellow, Emerald, VS1
Analysis:
A very large fancy intense yellow emerald cut diamond, polished with a facet alignment typically seen in colorless diamonds. The color dispersion is very low and the inner grade is average. There is no green or brown undertone present in the hue. The color distribution is uneven on the report.
High Auction Estimation: $ 17,987 pc
Price realized: $28,272 pc
Rarity: Once every 2-3 years – Share this rarity result – Here
GIA Report: View
Visual Assets:
Inner Grade..……………….3
Color Dispersion.…….…1
Undertone..…………………3
Total Visual Score….7 out of 12
Quality Remark: Low color dispersion
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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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