Sotheby’s Geneva November Diamond Recap – Several Lessons in Color Grading
Gary Roskin –
Roskin Gem News Report –
13 November 2024
Geneva
The Magnificent Jewels Sale this past November in Geneva featured quite a few fancy color diamonds, with four that really caught our attention.
The first, of course, was the Fancy Red—a highlight of the auction. The color grade and general quality notations are fairly straightforward, but it’s always important to discuss the rarity of a red diamond.
Next was the large round brilliant Very Light Pink, which sold for 1.2 million. The color grade of “Very Light Pink” isn’t considered a “Fancy” color grade, so why the big price tag? We need to clarify a few details about this one.
Then, there was the Fancy Orangy-Pink diamond that sold for more than three times its high estimate, raising the question: why? We think we have an idea.
And finally, there’s the Fancy Intense Yellow, which, based on the photos in the catalog, appears to be very close to a Fancy Vivid. Let’s discuss the challenges of grading based on catalog images and grading reports.
Diamond Lesson 1
Spectacular and Very Rare Fancy Red Diamond Ring
Claw-set with a cut-cornered rectangular mixed cut fancy red diamond weighing 1.44 carats, along with an Argyle mine presentation case.
This diamond is accompanied by GIA report no. 5212594746, dated 18 March 2022, stating that the diamond is Fancy Red, Natural Color, I2 Clarity; together with an Argyle Pink Diamonds gem identification and authenticity document no. 410369, dated 1 June 2022.
Estimate: 900,000 – 1,800,000 CHF
Lot Sold: 960,000 CHF
This is a Diamond with History
This special diamond was originally sold in the Rio Tinto 2021 Argyle Pink Diamonds Tender: Lot 32, Red, P1 (clarity) and is inscribed on the girdle with the Argyle logo as well as the Argyle grading report number. (GIA graded the diamond as Fancy Red, I2 clarity.)
For those unfamiliar with the Argyle Pink Diamonds Tenders, when Western Australia’s Argyle Diamond Mine was still in operation, the best of the best fancy colors from each year’s production were offered to the trade through an invitation-only silent bid auction. The most important diamonds in each Tender were designated as “Heroes.” Although this 1.44-carat Fancy Red diamond is exceptionally rare, we did not find it listed among the 2021 Argyle Tender’s “Hero Stones.” If we had to take an educated guess as to why not, we would say that its clarity most likely prevented it from earning one of the top spots.
Grading Fancy Red Color
Very few Fancy Red diamonds exhibit a “ruby red” or “stoplight red” appearance. More common descriptions include “garnet red” or “brick red,” which are frequently associated with Fancy Red diamonds.
Secondary colors, such as purple, orange, or brown, can complement the diamond’s primary red body color. These secondary hues are common in red diamonds but are only noted when apparent in the face-up position. In the trade, being graded Fancy Red without a secondary hue is preferred.
Based on the catalog images, this particular diamond may show a slight orange or purple secondary hue. However, the hue is evidently subtle enough that it was not noted on the Fancy Red grading report.
Note: The GIA does not use saturation modifiers for red diamonds. Red is considered the ultimate darker and strong saturated form of pink. Therefore, terms like “Fancy Vivid Red” or “Fancy Intense Red” do not exist. If a diamond is red, it is simply graded as “Fancy Red.”
Clarity in Fancy Color Diamonds
This diamond’s clarity grades—P1 by Argyle and I2 by GIA—may have impacted its value, as it sold at the lower end of the estimated 900,000 CHF. In fancy color diamonds, clarity generally only affects value when the inclusions are eye-visible and detract from the diamond’s overall beauty. Conversely, in higher clarity grades, such as VVS or Internally Flawless/Flawless, rarity significantly impacts value. (Clarity grades such as VS and SI often have little to no effect on value in fancy color diamonds.)
Diamond Lesson 2
Impressive Very Light Pink Diamond Pendant
Accompanied by GIA report no. 5192207827, dated 26 March 2018, stating that the brilliant-cut diamond weighing 16.73 carats, measuring 16.40 – 16.45 x 10.07mm, is Very Light Pink, Natural Colour, VVS1 Clarity, Excellent Polish and Symmetry; together with a type IIa classification letter.
Fancy Color Grading – Where Does it Begin?
When you examine the GIA Fancy Color grading chart, you find that Very Light Pink, the color of our diamond here, is not in the Fancy color portion of the scale. Fancy color in Pink ranges in least to most saturation from Fancy Light to Fancy, then Fancy Intense, and most valued Fancy Vivid. Then on the darker tone and greater saturation side we find Fancy Dark, then Fancy Deep, and then, lo and behold, with enough saturation and darker tone (as noted above) it is Fancy Red.
So where is Very Light Pink?
As one goes lighter in tone and less in saturation from Fancy Light Pink, towards near colorless, you move out of the Fancy range to Light Pink, then even lighter to our auction round brilliant’s Very Light Pink, and then even further away from Fancy, is Faint Pink. (After that, you don’t see pink.)
Verbal Description of Color Grades
Back in the day when Fancy color Masters were non-existent, there were word descriptions used to grade fancy color. An older definition of Very Light states that “if the tint is just seen at the points, or on the sides when face up, use the term ‘Very Light’.” Judging from the picture, and according to descriptive terminology, this diamond should fall in the Very Light Pink category. Consider the image of the model wearing the necklace, where the pink color is barely visible at the edges.
Size and Color
One mention here should be regarding the diamond’s weight/size. Larger diamonds show more color than the grade would suggest. Because this round brilliant is almost 17 carats, we should expect more visible face-up color, and still consistent with the size of the diamond, graded as Very Light Pink.
Cutting and Color
If you take a look at the GIA grading report, you will see that this diamond seems to have very good proportions for a colorless round brilliant – maximizing the diamond’s brilliance. Cutting to maximize brilliance may then be masking the color, enhancing more white light – hiding the pink. Some disagree with this theory, but it may be something that is driving speculation.
Something Else to Consider
With the extra weight, weight above 15 carats, one might consider recutting the stone, deeper and steeper to hold more saturation face-up, maybe even enough to change the color grade from Very Light Pink to Light Pink, or even Fancy Light Pink. Would the potential increase in value, appearance, and salability be worth the recutting?
Stamped PT950 for platinum. On a transparent nylon cord, length approximately 360mm, transparent nylon chord irregular. In good condition. Gross weight approximately 11 grams.
Estimate: 720,000 – 1,100,000 CHF
Lot Sold: 1,260,000 CHF
Diamond Lesson 3
Impressive Fancy Intense Yellow diamond ring
Accompanied by GIA report no. 1226749732, dated 13 December 2022, stating that the cushion modified brilliant-cut diamond weighing 40.88 carats, measuring 21.11 x 17.73 x 12.35mm, is Fancy Intense Yellow, Natural Colour, VS2 Clarity, Excellent Polish and Symmetry.
Stamped 750 for 18 carat gold. In very good condition. Gross weight approximately 13 grams.
Estimate
Estimate: 630,000 – 700,000 CHF
Lot Sold: 720,000 CHF
Color Grading Fancy Intense vs. Fancy Vivid
The difference between Fancy Intense and Fancy Vivid can range from barely noticeable to quite significant. Fancy, Fancy Intense, and Fancy Vivid are color ranges. They butt right up next to each other, so the difference can be almost indistinguishable, or the difference can be as much as an entire grade apart.
When you look at this diamond, you see a vibrant even saturation of yellow. From past experience, what we see is a saturated color close to Vivid. But there are two caveats here; 1. We’re guessing, grading without masters, and 2. We’re grading a picture on a computer screen or a phone.
We can either tell ourselves that the diamond is a highly saturated “Fancy Intense,” which is why the selling price was so strong, or that the buyer believes it is too close to Vivid not to gamble—using the 88 points from the 40.88 cts. to recut the diamond in order to concentrate more face-up color, and then resubmit it to the lab in hopes of getting a “Fancy Vivid Yellow” grade.
So the question is, which monitor should we use? (We are joking, of course!)
Diamond Lesson 4
Attractive Fancy Orangy Pink Diamond Ring
Set with a step-cut fancy orangy pink diamond weighing 12.52 carats between triangular diamond shoulders. The diamond is accompanied by GIA report no. 1206974642, dated 16 March 2020, stating that the diamond is Fancy Orangy Pink, Natural Color, VVS2 Clarity.
Estimate: 500,000 – 800,000 CHF
Lot Sold: 2,880,000 CHF
Why?
Why did we raise our eyebrows at this particular diamond? It’s not anything unusual – is it? It’s graded Fancy, not Fancy Intense or Fancy Vivid. Is Orangy-Pink that rare? It is pretty.
Answer: The question stems from the estimated value to the selling price. The high estimate was 800,000 CHF, but it sold for 2,80,000 CHF! (That’s just over $3 million!) What we can determine from the GA report is that the clarity grade is VVS2 and appears to be improvable with minor recutting. So clarity could go up without going below 12 carats. Maybe with a half carat to work with, recutting could improve the color grade, moving from Fancy to Fancy Intense?
Henry Grossbard of the Radiant Cut Diamond Company in New York developed and patented the Radiant Cut. He would take emerald cuts and reshape them into Radiant cuts, which was very good at improving fancy color. Maybe this diamond will get a make-over and become a Radiant cut, punching up the color to Fancy Intense, and a higher clarity.
Or maybe they simply love the color – a Padparadscha Diamond – of the emerald cut and will leave well enough alone. 😊
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