blue diamond – Page 2 – The Diamond Certification Laboratory of Australia (DCLA)

Antwerp Diamond Polishers Develop Device That Uses AI to Grade Colored Stones

Chroma Diamonds founded by Alexander Appels and Jan De Henau is a relatively new company in the Antwerp diamond district, which specializes in colored diamonds. Stymied by the relatively “subjective process of color grading”, the 2 have set out on a mission to develop a device that provides more objective measurements for the grading of colored stones.

The device will utilize AI gathering data points and becoming smarter with each new set of inputs. They believe with sufficient time the device would learn enough to be able to more accurately grade certain stones, especially in resolving cases where certain grading criteria place the value of diamond on the edge of a color category but not quite enough to satisfy it being classified in the next grade above.

“Customers come to us with high expectations. After all, the value of their diamond is determined by, among other things, the color and intensity of that color, and let it (partly) depend on the cut and the people in the grading office, we hear. Because it is they who assign the diamond an official color, and therefore also determine its value definitively,” explains Appels.

Though this idea is not new to the Diamond District the duo has taken things one step further receiving support from the innovation process of the City of Antwerp. They plan on using and testing the device in their own business first as proof-of-concept before taking it to the greater market.

Source: Bloovi

$15M Blue Diamond to Hit Christie’s Auction Block

A blue diamond pendant will be among the headliners in next month’s Christie’s sale in New York, where it is expected to bring in up to $15 million.

The pear modified brilliant-cut, 31.62-carat, fancy-blue stone, surrounded by white and pink diamonds, is potentially internally flawless, Christie’s said Tuesday. A pear brilliant-cut, 86.64-carat, D-color, VVS1-clarity diamond pendant will join it at the December 6 Magnificent Jewels sale. That piece, which hangs from a chain of 78 diamonds between 0.50 and 2.50 carats, is estimated at $5 million to $7 million.

Other notable items include a torque bangle bracelet bearing a heart brilliant-cut, 50.05-carat, D-color, internally flawless diamond, with a presale price of $3.7 million to $4.5 million. A modified pear double rose-cut, 5-carat, fancy-vivid-blue diamond ring has an upper estimate of $4 million and no reserve. An oval brilliant-cut, 51.60-carat, G-color, VS2-clarity diamond ring carries a high price of $2.8 million.

Christie’s will also offer an unmounted modified pear brilliant-cut, 104.04-carat, fancy-intense-yellow diamond. That jewel has an upper estimate of $2.5 million, as does a round-cornered square brilliant-cut, 107.46-carat, fancy-yellow diamond brooch by Graff. Meanwhile, an emerald-cut, 13.75-carat, fancy-vivid-yellow, internally flawless diamond ring by De Beers and an oval brilliant-cut, 2.21-carat, fancy-intense-blue diamond ring are set to fetch up to $1.8 million each.

Those items join the star of the show: An emerald-cut, 13.15-carat, fancy-vivid-pink diamond ring that Christie’s expects will fetch up to $35 million at the auction.

Source: Diamonds.net

De Beers Blue Diamond Fails to Sell at Sotheby’s

A blue diamond weighing 5.53 carats failed to find a buyer at Sotheby’s Geneva on Wednesday despite being billed as the star of the auction.

The cushion brilliant-cut, fancy-vivid-blue diamond is part of an eight-piece group called the De Beers Exceptional Blue Collection, which Sotheby’s has spread between its various Magnificent Jewels sales. No bids matched the stone’s threshold price for sale, according to a post-auction report by the Fancy Color Research Foundation (FCRF). The piece carried a presale estimate of $11 million to $15 million.

“The blue is an exceptional stone in every sense,” Sotheby’s told Rapaport News Thursday. “It attracted significant interest prior to yesterday’s sale. While we didn’t get to see it sell in the room last night, we are confident it will find a new home very soon.”

Meanwhile, a number of items set records at the November 9 sale, including a 20.16-carat sapphire and diamond ring from Cartier. That piece, which fetched $2.8 million against a high estimate of $2 million, saw a record price per carat for any blue sapphire of Burmese origin ever sold at auction. A 20.58-carat, pink sapphire ring also broke the record for per-carat price, bringing in $1.9 million, or $91,690 per carat, well above its $808,368 upper price tag. A pink sapphire and diamond brooch weighing 92.01 carats by Jean Schlumberger sold for $1.8 million, outstripping its $505,278 high estimate and setting a record price for a piece of jewelry by the designer.

Another notable item at the sale was a pair of unmounted oval-cut, D-flawless diamonds weighing 20.03 and 20.19 carats. The duo fetched $4.2 million, within estimates. A step-cut, 33.13-carat, D-color, VVS1-clarity diamond ring by Cartier brought in $2.9 million, also within its expected range.

The entire Geneva Magnificent Jewels auction garnered $50 million. Sotheby’s will offer two more blue diamonds from the De Beers collection at its upcoming New York Magnificent Jewels sale on December 7.

Source: Diamonds.net

Collection of Blue Diamonds to Fetch Over $70M

Sotheby’s will sell a group of eight fancy-blue diamonds from De Beers across its global Magnificent Jewels auctions, expecting the set to bring in more than $70 million.

The stones are cut in various shapes and range from 1.22 to 11.29 carats, with a total weight of 32.09 carats, Sotheby’s said last week. The polished originates from five rough blues that De Beers and Switzerland-based manufacturer Diacore purchased jointly from Petra Diamonds in November 2020. Diacore cut and polished those stones into eight diamonds over the past two years.

Sotheby’s will offer three stones from the eight-piece group, called The De Beers Exceptional Blue Collection, this year. The first, a cushion brilliant-cut, 5.53-carat, fancy-vivid blue diamond will go under the hammer at the Magnificent Jewels and Noble Jewels sale in Geneva on November 9, with a high estimate of $15 million. Meanwhile, the December 7 Magnificent Jewels sale in New York will feature a cushion brilliant-cut, 3.24-carat, fancy-vivid blue, internally flawless diamond estimated at up to $8 million. That jewel will be joined by a cushion-cut, 2.08-carat, fancy-intense-blue diamond with an upper price tag of $1.5 million.

“I have remained in awe of the De Beers Exceptional Blue Collection since the first moments I set eyes on it,” said Olivier Wagner, head of Sotheby’s Magnificent Jewels auctions in Geneva. “The market for colored diamonds and precious gemstones has never been stronger. [The diamonds] will, I am sure, captivate all collectors of exceptional gemstones.”

Sotheby’s will sell the remaining five diamonds at its spring 2023 Magnificent Jewels auctions. Those include a step-cut, 11.29-carat, fancy-vivid-blue estimated at up to $50 million; a step-cut, 4.13-carat, fancy-intense-blue expected to go for up to $3.5 million; and a cushion brilliant-cut, 3.10-carat, fancy-vivid-blue diamond with a high price of $5 million.

In April, Sotheby’s sold another De Beers blue diamond: a step-cut, 15.10-carat, fancy-vivid-blue, internally flawless stone that went for $57.5 million in Hong Kong.

Source: Diamonds.net

Sotheby’s Rakes In $57.5M for De Beers Blue

A record blue diamond co-owned by De Beers far outstripped its presale estimate in a stand-alone sale at Sotheby’s in Hong Kong, garnering HKD 450.9 million ($57.5 million), the auction house said Wednesday.

*The 15.10-carat De Beers Cullinan Blue diamond*

The step-cut, 15.10-carat, fancy-vivid-blue, internally flawless stone, called the De Beers Cullinan Blue, is the largest of its color to appear at auction. The stone, which sold to an unnamed buyer, had been expected to fetch up to $48 million.

Petra Diamonds discovered the 39.35-carat rough in April 2021 at its Cullinan mine in South Africa. In July, De Beers and Diacore bought the stone for $40.2 million, and Diacore manufactured the piece into the final polished.

To date, only five blue diamonds weighing more than 10 carats have come to auction, none of which has exceeded 15 carats, Sotheby’s explained. Similar blue diamonds have also fetched high prices, including the Blue Moon of Josephine, a cushion-shaped, 12.03-carat, fancy-vivid-blue, internally flawless diamond that sold for $48.5 million at Sotheby’s Geneva in 2015. Meanwhile, the Oppenheimer Blue, a step-cut, 14.62-carat, fancy-vivid-blue, VVS1-clarity stone, garnered $57.5 million at a Christie’s Geneva sale in 2016.

Source: Diamonds.net

De Beers Cullinan Blue Diamond Could Bring $48M at Auction

Sotheby’s will auction a stone described as “the largest vivid blue diamond ever to appear at auction” on April 27 in Hong Kong.

Sotheby’s estimates that it could bring $48 million.

The 15.1 carat step-cut blue was cut from a rough stone discovered in April 2021. It is “the largest internally flawless step cut vivid blue diamond that the Gemological Institute of America (GIA) has ever graded,” according to a press statement.

“This diamond ranks as one of the best De Beers has ever seen,” said Bruce Cleaver, CEO of De Beers Group. “It is extremely rare and unique, and as the Home of Diamonds, De Beers is pleased to join together with Sotheby’s to bring this diamond to the world.”

Only five blue diamonds over 10 carats have ever come to auction, Sotheby’s notes. Until now, none has exceeded 15 carats.

“Blue diamonds of any kind are rare on the market, but this is the rarest of the rare; nothing of remotely similar calibre has appeared at auction in recent years,” says Patti Wong, chairwoman of Sotheby’s Asia. “Hundreds of millions of years in the making, this extraordinary blue diamond is surely one of nature’s finest creations.”

The diamond comes from the Cullinan mine in South Africa.

Source: instoremag

Colored Diamonds Set to Sparkle at Sotheby’s

6.11 *carat, fancy intense blue diamond ring*

A blue diamond ring is among the top lots at the Sotheby’s Magnificent Jewels sale in New York next month.
The piece contains a cut-cornered rectangular modified brilliant-cut, 6.11-carat, fancy-intense-blue, VS2-clarity diamond surrounded by round diamonds. It is estimated to bring in up to $6.5 million at the December 7 auction, Sotheby’s said Monday.

A cut-cornered rectangular mixed-cut, 6.69-carat, fancy-intense-pink, VS2-clarity diamond ring with a high valuation of $6 million will also star in the sale, as will a cushion-cut, 3.01-carat, fancy-vivid-blue diamond. The stone, which is set in a ring and flanked by two heart-shaped diamonds, is expected to sell for up to $4.5 million.

Other notable items include a pear-shaped, 62.65-carat, D-color, VVS2-clarity diamond ring with a high price tag of $3.5 million, and an emerald-cut, 9.97-carat emerald and diamond ring with an upper valuation of $2.5 million.

An unmounted, heart-shaped, 15.01-carat, D-color, internally flawless diamond will also be up for grabs. The stone, which is being offered without reserve, has a high estimate of $2.5 million. Sotheby’s is collaborating with Brilliant & Black designer Lauren Harwell Godfrey to make a finished jewelry piece for the diamond, it noted. She has created two original designs that utilize her signature triangle inlay pattern — for a necklace and a ring.

Meanwhile, 30 jewels from an American private collector will also go under the hammer. The entire group is estimated at more than $6 million and includes one of the most significant collections of Bulgari pieces ever to come to market, Sotheby’s explained.

In total, the auction house will offer more than 200 lots, with the sale forecast to fetch as much as $70.1 million — the highest estimate for a New York Magnificent Jewels sale since December 2018, Sotheby’s added.

Source: Diamonds.net

20-Carat ‘Okavango Blue’ Diamond Goes on Display

The public can now feast their eyes on a big blue diamond thanks to New York’s American Museum of Natural History. The museum opened an exhibition Tuesday showcasing the “Okavango Blue,” a 20.46-carat oval-cut fancy deep blue diamond on loan from Okavango Diamond Company, which is wholly owned by the government of Botswana.

It has been given a VVS1 clarity grade from GIA. The diamond came from Botswana’s Orapa mine and is the largest of its kind found in the country to date. The Okavango Blue was named after Botswana’s Okavango Delta, a UNESCO World Heritage Site of global importance for biological conservation and diversity. It’s the first time the diamond is on view to the public and sits at the center of a larger presentation about diamonds from Botswana, exploring industrial uses for diamonds and how Botswana runs its diamond industry as well as educating about the different characteristics of diamonds like size, shape, color, and quality. Botswana is the second-largest producer of natural diamonds in the world, behind Russia. Previous

The Okavango Blue Diamond, pictured here in the center display, is part of a presentation about the variety of natural diamonds found in Botswana. (Photo credit: D. Finnin/©AMNH) — The Okavango Blue Diamond, pictured here in the center display

Next “Our natural diamond resources are managed responsibly in a manner that puts the people of Botswana first,” said Okavango Diamond Company Managing Director Mmetla Masire. “There is a strong sense of local pride knowing that these diamonds are improving the lives of Batswana, with profits directly reinvested in education, infrastructure, and public health. “We are so pleased to share with the world the larger story of the diamond industry of Botswana. The Okavango Blue is not just an ordinary 3-billion-year-old polished carbon element, but rather a physical embodiment of the passing of time, a fragment of eternity. Our diamonds tell the rich history and unique journey of Botswana’s development.” The exhibition sits in the Melissa and Keith Meister Gallery in the museum’s new Allison and Roberto Mignone Halls of Gems and Minerals, which reopened in June after a major renovation. The Okavango Blue and its corresponding Botswana diamonds exhibition will run for six months, AMNH confirmed.

Source: nationaljeweler

Blue rough diamond fetches $40 million

Petra Diamonds Ltd. sold a 39.3-carat blue gem for more than $40 million, making it one of the most expensive rough diamonds ever.

The small miner sold the exceptional Type IIb blue diamond to a joint venture between top producer De Beers and Diacore, a trading company owned by the billionaire Steinmetz family, it said Monday. The stone fetched just over $1 million per carat and is the most expensive gem Petra has ever sold.

Petra found the diamond at the Cullinan mine in South Africa in April. The mine, once owned by De Beers, is famous for both large and blue stones and was where world’s biggest diamond was found in 1905. Blue stones are among the most rare and valuable.

The sale is good news for Petra, which was forced to restructure its debt last year, when the Covid-19 crisis brought the industry to a standstill at a time when the company was already facing a mountain of debt and falling diamond prices. The shares, which were once worth more than $1.5 billion, closed up 1.1% on Monday.

Petra puts “exceptional” 39-carat blue diamond up for sale

39.34 carat blue diamond recovered by Petra South Africa

South Africa’s Petra Diamonds has put a 39.34 carat Type IIb gem recovered at its iconic Cullinan mine in April up for sale, with viewings beginning June 15.

The company said the diamond of “exceptional quality” in terms of both its colour and clarity, will be showcased in Antwerp, Dubai, Hong Kong and New York.

Petra, which anticipates that the diamond will be sold via a special tender, said that biddings via its online platform will close on July 12.

While it didn’t set a price range for the stone, the miner said high-quality blue diamonds like the one for sale usually fetch the highest values.

Petra’s Blue Moon of Josephine diamond, cut from a 29 carat rough blue diamond, sold for $48.5 million in 2015.

The figure corresponds to a price of $4 million per carat, which remains the world record price per carat ever paid for a diamond.

Cullinan is known as the world’s most important source of blue diamonds, as well as being the birthplace of the 3,106-carat Cullinan diamond, which was cut to form the 530-carat Great Star of Africa. The operation also yielded the 317-carat Second Star of Africa. They are the two largest diamonds in the British Crown Jewels.

Source: Mining.com