Roskin Gem News Report

Magnificent Blue Jewels

Gary Roskin speaking with Sotheby’s Frank Everett prior to the auction.
Photo by Liz Chatelain.

Some of the many beautiful pieces of the Sotheby’s Magnificent Jewels auction that caught our attention, are here in the Roskin Report.

Up first, a Frank Everett favorite. You’ve probably seen Frank (SVP, Deputy Chairman, Jewelry Americas) on Sotheby videos called Frank’s Files, speaking out about specific pieces of jewelry that are coming up for auction.

One of his favorite pieces of the auction, a Cartier, Sapphire and Diamond Clip-Brooch, Paris. Designed as a flower, the petals are embellished with round and oval-shaped sapphires, the pistil and leaves accented by round diamonds, and the stem set with baguette diamonds. Signed Cartier Paris, and numbered HSA41285 and 013471, with French assay and maker’s marks; circa 1958. Even comes with a signed pouch.

With an Estimate of between $30,000 and $50,000 USD, the piece sold for $69,850.

Accompanied by 1. a Cartier Certificate of Authenticity, and 2. an SSEF report no. 118559 dated September 14, 2021 stating that the sapphires are natural, a majority originating from Burma, a majority with no indications of heating, with a few having minor amounts of oil in the fissures.

Paraíba Tourmaline and Diamond Ring

Paraiba tourmalines are cuprian (copper-bearing) elbaite tourmaline. They are unique in that they get their color from the presence of trace amounts of copper.

This pear modified brilliant-cut Paraíba tourmaline weighing 4.87 carats, and accented by round and marquise-shaped diamonds, was estimated to sell for somewhere between $50,000 and $80,000 dollars. It sold for $241,300!! That puts the value of the gem at just under $50,000 per carat!

While this pear shape has vivid color saturation, one laboratory cannot give a country of origin, and another couldn’t determine if the gem had been treated to improve clarity and/or color.

  1. 1. Accompanied by Gübelin report no. 19091068 dated September 18, 2019, stating that the Paraíba tourmaline is of Brazilian origin, with undeterminable treatment.

2. Accompanied by GIA report no. 3275228579 dated October 19, 2017 stating that the Paraíba tourmaline is of Brazilian origin.

3. Accompanied by AGL report no. 1129765 dated March 14, 2023 stating that the Paraíba-Type tourmaline is of undeterminable origin, with no indications of clarity enhancement.

The Sapphire and Diamond Necklace

In one section of the sale, “Extraordinary Jewels from the Collection of Constance Prosser Mellon” were for sale.

Here is a Cartier, Sapphire and Diamond Necklace

“Of swag design, featuring five emerald- and square emerald-cut sapphires weighing 10.01, 7.66, 7.35, 5.45 and 4.44 carats, accented by round, baguette and square-cut diamonds; circa 1950. Comes with a signed, fitted box.

The sapphires are Kashmir, with no evidence of heat treatment.

It was estimated to sell between $2,000,000 & $3,000,000 USD, and it sold for just under $3 million at $2.843 million.

Coming to an End with our Report …

And one last treat here, but you can always tap to Sotheby’s to see the full sale, from the “Extraordinary Jewels from the Collection of Constance Prosser Mellon,” here is a Cartier, Sapphire and Diamond Ring.

“Featuring an emerald-cut sapphire, weighing 33.51 carats, and accented by baguette diamonds.” This ring received plenty of attention.

Estimated to sell between $1,500,000 & $2,500,000 USD, it sold for $3,266,500 USD.

Accompanied by AGL report no. 1101654, dated June 25, 2019, stating the sapphire is of Classic Burmese origin, with no indications of heating. Together with a letter from the AGL stating that this color variety of sapphire may also be called ‘royal blue’ based on AGL reference standards.

Accompanied by Gübelin report no. 23022090 dated March 1, 2023 stating that the sapphire is of Burmese origin, with no indications of heating, this color variety of sapphire may also be called ‘royal blue’ by members of the trade.

Tap here to go to Sotheby’s auction results.

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