A yellow diamond ring was the star of the most recent jewelry sale at Phillips in Hong Kong, fetching HKD 8.9 million ($1.1 million).
The round brilliant-cut, 15.51-carat, fancy-vivid-yellow, VS2-clarity diamond ring fell within its estimated range at the March 28 Hong Kong Jewels auction, Phillips said last week. In total, the sale achieved HKD 32.3 million ($4.1 million), with 73% of items finding buyers.
“The sale total for our spring auction in Hong Kong increased by 20% over the previous season, demonstrating the resilience of the global demand for rare and important jewels across the board,” said Benoît Repellin, worldwide head of jewelry for Phillips. “Fancy colored diamonds commanded the sale…. Vintage signed pieces also performed well. We also saw notable demand for [the] finest Burmese rubies, emeralds and sapphires.”
Here are the rest of the top five jewels at the sale:
This Van Cleef & Arpels necklace, created in 1985, is set with alternating brilliant-cut diamonds and round cabochon turquoises, supporting a fringe of pear-shaped cabochon turquoises. It realized HKD 4.6 million ($584,302), nearly four times its HKD 1.2 million ($150,000) high estimate.
A ring bearing a pear-shaped, 2.65-carat, fancy-intense-orangey-pink, VS1-clarity diamond brought in HKD 2.9 million ($373,304), within estimates.
Phillips sold this brilliant-cut, 5.53-carat, D-color, VVS1-clarity diamond ring for HKD 1.9 million ($243,459), at the upper end of its price range.
A bracelet with 12 cushion-shaped, oval and circular-cut Burmese rubies weighing approximately 24.59 carats in total, as well as kite-shaped diamonds, went for HKD 1.5 million ($194,767), missing its HKD 1.8 million ($230,000) lower presale price.
A 133.03 carat Fancy Vivid Yellow diamond achieved a sale price of more than $5.5 million, becoming the largest fancy vivid yellow diamond to sell at auction.
This was the top lot at Sotheby’s December 5 Magnificent Jewels auction in New York. The unmounted cushion modified brilliant-cut gem with VS2 clarity surpassed its high estimate of $5 million.
The diamond was purchased by Diacore, a diamond manufacturer best known for crafting rare, exceptional diamonds and high-end jewelry.
The company also has a joint partnership with Sotheby’s called “Sotheby’s Diamonds,” in which they manufacture and market diamonds specifically for private sale at Sotheby’s locations in London, New York and Hong Kong.
A 10.19-carat yellow diamond ring will lead an upcoming auction at Bonhams in London, where it is set to fetch up to GBP 160,000 (approximately $199,300).
Bonhams will offer the radiant-cut, fancy-intense-yellow, VS1-clarity stone, set between shield-cut diamond shoulders, at its December 7 London Jewels auction, it said Tuesday.
Two additional yellow diamonds for sale include a brilliant-cut, 10.02-carat, fancy-yellow diamond single-stone ring and a step-cut, 8.45-carat, fancy-yellow diamond ring accented by four pear-shaped diamonds set between baguette and step-cut diamond shoulders. Both pieces carry estimates of GBP 50,000 to GBP 70,000 (approximately $62,300 to $87,200).
The 149-lot auction will also feature pieces from multiple single-owner private collections, spanning from 1870 to the modern day. These comprise jewels from Cartier, Bulgari, Graff, Moussaieff, Van Cleef & Arpels, Harry Winston, Boucheron, Tiffany & Co., David Webb, and Grima.
Highlights from a single-owner private European collection are a Lalique Art Nouveau enamel, pâte-de-verre, sapphire and diamond pendant from around 1905 to 1915; a Cartier Panthère coral, emerald, onyx and diamond brooch, circa 1968; and a Cartier ruby and diamond clip and ear clip suite brooch combination that dates to about 1960.
Another collection, from a descendant of Dorothy Maud, Countess Haig, boasts a pearl and diamond tiara necklace presented to the countess by Queen Alexandra in 1905 on her marriage to General Haig.
A pair of fancy vivid orange-yellow diamond earrings weighing 12.20 and 11.96 carats will be the top lot at Christie’s Magnificent Jewels sale on December 6 in New York. The earrings, which are named “California Sunset Diamonds,” are estimated at $7 million – $12 million.
A ring with a similar fancy vivid yellowish orange diamond weighing 5.16 carats has an estimate of $1.5 million – $2 million.
A 5.16-carat fancy vivid yellowish orange diamond has an estimate of $1.5 million – $2 million CHRISTIE’S
There haven’t been many details released yet for Christie’s final jewelry auction of 2023, but the sale will include several fancy colored diamonds, white diamonds and colored gems. As always, there will be signed jewels from important collections.
In celebration of Haute Couture Week, Graff is exhibiting a collection of yellow diamonds at its flagship Paris boutique to complement the unveiling of its new high jewellery necklace
Launched yesterday (4 July 2023), visitors to Sunrise: A Celebration of Graff Yellow Diamonds will discover a world of rarity and lustre through a stunning showcase of high jewellery pieces featuring rare yellow diamonds, accompanied by displays detailing Graff’s storied history with these incomparable stones.
The House’s latest high jewellery creation features an extremely rare 30ct fancy intense yellow pear shape diamond, accompanied by a further 138ct of yellow and white diamonds.
Every element of the piece has been created using the stone-led design techniques for which the Graff atelier is renowned and has been crafted to emphasise the elegant silhouette of the centre stone.
Graff design director, Anne-Eva Geffroy explained: “Before we design, we study each diamond carefully to uncover the secrets that lie within its depths.
“Only then do we design, and when we do, we work to accentuate the natural beauty of each stone.
“The fancy intense yellow diamond set into this piece gives a golden sunshine glow.
“Yellow diamonds bring so much joy.
“It is an honour to be inspired by stones that radiate such beauty.
“The yellow diamonds we work with are exceptional in quality, cut, and quantity.
“Very few jewellers have the luxury of such a wide range of colour.”
In vibrant halos of yellow and white diamonds, stones radiate outwards from the central fancy intense yellow diamond to replicate the rays of the sun.
A perfect synthesis of diamond design and hand-craftsmanship, each bespoke setting has been meticulously assembled by master artisans within the House’s London workshop.
CEO of Graff, Francois Graff added: “Celebrating Graff’s legacy of innovation and leadership in presenting the highest quality rare diamonds, this will be the most significant collection of yellow diamonds that have ever been brought together in one place, including a fancy intense yellow stone of incomparable beauty.
“These are truly jewels that represent the very best of Graff.”
Further pieces on display in the showcase at the flagship Paris boutique include unique high jewellery necklaces, Tribal-inspired jewels, earrings, and single-stone rings that unmistakably express Graff’s design DNA through the combination of superb stones with bold designs and unparalleled craftsmanship.
An impressive roster of important and famous yellow diamonds have passed through the House over the course of its history, beginning with the Star of Bombay in 1974.
The Star of Bombay is an historical yellow stone that was re-cut and polished by Graff using revolutionary expertise and new techniques.
Since then, Graff has introduced many famous and historical yellow diamonds over the years, including the 118.08ct Delaire Sunrise and the 132.55ct honey-hued Golden Empress.
Sunrise: A Celebration of Graff Yellow Diamonds is currently exhibiting at Graff Rue Saint-Honoré throughout Haute Couture Week in Paris.
Argyle pink diamonds are extremely rare and highly sought-after, making them some of the most valuable diamonds in the world. The Argyle diamond mine in Western Australia is the primary source of pink diamonds, and it is estimated that only 0.01% of the diamonds recovered from the mine are pink in colour, with an even smaller percentage being of the highest quality.
The Argyle mine ceased operations in 2020, which has led to speculation that the prices of pink diamonds, including argyle pink diamonds, may increase in the coming years. With the mine no longer producing new stones, the limited supply of these rare diamonds is expected to drive up demand and prices. However, like any investment, it’s important to carefully consider market trends and consult with a qualified professional before making any decisions.
The largest pink argyle diamond found to date is the Argyle Pink Jubilee, which was discovered at the Argyle mine in Western Australia in 2011. The diamond weighs 12.76 carats and is a vivid pink colour, making it one of the largest and most valuable pink diamonds ever found. The Pink Jubilee was cut and polished over a period of ten months, during which time the rough diamond was studied and analyzed extensively to determine the best way to bring out its natural beauty and maximize its value. The diamond was sold at auction in 2013 for an undisclosed sum, but it is believed to have fetched a record-breaking price per carat for a pink diamond.
Red diamonds are extremely rare, even more so than pink diamonds. It is estimated that only a handful of natural red diamonds are found each year, and most of them are less than half a carat in size. Red diamonds are so rare that many jewelers and gemologists may go their entire careers without ever seeing one.
The red colour in diamonds is caused by the presence of a rare mineral which causes “graining,”, This occurs when the crystal structure of the diamond is distorted during its formation. The graining causes the diamond to absorb green light and reflect red light, resulting in a beautiful and distinctive red hue. Because of their rarity, red diamonds are among the most valuable and expensive gemstones in the world. They are highly sought-after by collectors and investors, and prices for top-quality stones can reach millions of dollars per carat at auction.
Blue diamonds are also quite rare, but not as rare as pink or red diamonds. Blue diamonds account for only about 0.02% of all diamonds mined worldwide. The blue colour in diamonds is caused by the presence of trace amounts of boron during their formation, which causes the diamond to absorb red, yellow, and green light, resulting in a blue hue.
Blue diamonds are highly prized for their unique colour and rarity, and they can command very high prices at auction. The value of a blue diamond depends on a variety of factors, including its size, colour intensity, clarity, and overall quality. Blue diamonds range in colour from pale blue to vivid blue, with the most valuable stones being those with a deep, rich blue colour.
One of the most famous blue diamonds is the Hope Diamond, which is a 45.52-carat blue diamond that is part of the Smithsonian Institution’s collection of natural history specimens.
The most expensive diamond ever sold is the Pink Star, a 59.60-carat oval-cut pink diamond that was sold for $71.2 million at a Sotheby’s auction in Hong Kong in 2017. The diamond, which is the largest internally flawless fancy vivid pink diamond ever graded by the Gemological Institute of America (GIA), was mined in Africa in 1999 and took two years to cut and polish.
The Pink Star was originally sold at auction in 2013 for a record-breaking $83 million, but the sale was later cancelled after the buyer defaulted on the payment. The diamond was put back up for auction in 2017 and sold to a jewelry retailer in Hong Kong for $71.2 million, setting a new world record for the most expensive diamond ever sold at auction.
Yellow diamonds are not as rare as pink, red, or blue diamonds, but they are still considered rare and highly prized. Yellow diamonds are formed when nitrogen atoms are trapped in the crystal lattice structure of the diamond during its formation, causing it to absorb blue light and reflect yellow light.
The intensity of the yellow colour in a diamond can vary widely, ranging from a pale yellow or light lemon colour to a deep, intense yellow. The most valuable yellow diamonds are those with a deep, rich colour that is evenly distributed throughout the stone.
Yellow diamonds are mined in various parts of the world, including South Africa, Australia, and Canada. While yellow diamonds are not as rare as some other coloured diamonds, high-quality yellow diamonds can still command very high prices at auction, especially those with a large carat weight and intense colour.
Orange diamonds are considered rare and highly valuable. The orange colour in diamonds is caused by the presence of nitrogen and other impurities in the crystal lattice structure of the diamond, which absorb blue and green light, resulting in an orange hue.
Orange diamonds can range in colour from pale orange to a deep, vivid orange, with the most valuable stones being those with a pure and intense colour. Orange diamonds are not as commonly found as white or yellow diamonds and are considered much rarer than brown or gray diamonds.
The most famous orange diamond is the Pumpkin Diamond, a 5.54-carat fancy vivid orange diamond that was mined in South Africa. The Pumpkin Diamond was sold at auction in 1997 for over $1.3 million, and it is now part of the collection at the Smithsonian Institution’s National Museum of Natural History in Washington, D.C.
The 303.10-carat Golden Canary fetched $12.4 million at Sotheby’s Magnificent Jewels in New York on Wednesday, becoming the third most valuable yellow diamond ever sold at auction, the company reported.
The pear-shaped, fancy-deep-brownish-yellow stone is the world’s largest known internally flawless diamond. It is also the largest flawless or internally flawless diamond graded by the Gemological Institute of America (GIA), Sotheby’s said Thursday. The auction house offered the piece without reserve, but predicted it would bring in more than $15 million.
The diamond was initially discovered in the Democratic Republic of Congo (DRC) in the early 1980s. Originally called the Incomparable Diamond, the stone was recut from its previous 407-carat shield shape to deepen the color and brighten the hue.
“The Golden Canary captivated me from the moment I saw it — with its monumental size, golden hue and impeccable clarity — it is truly an extraordinary diamond with immense presence,” said Quig Bruning, head of jewelry for the Americas at Sotheby’s.
Sotheby’s will offer a yellow diamond weighing more than 300 carats at its upcoming New York auction, where it is expected to bring in more than $15 million.
The pear-shaped, 303.10-carat, fancy-deep-brownish-yellow stone is one of the largest polished diamonds in the world. It is also the largest flawless or internally flawless diamond ever graded by the Gemological Institute of America (GIA), Sotheby’s said Monday.
Initially called the Incomparable Diamond, the stone was recut from its original 407-carat shield shape to deepen the color and brighten the hue, and renamed the Golden Canary. As the highlight of the December 7 Magnificent Jewels sale, it will be offered without reserve, with bidding starting at $1, Sotheby’s noted.
The Golden Canary was first discovered in the early 1980s in a pile of rubble by a young girl playing in the backyard of her uncle’s house, Sotheby’s noted. Miners from the nearby Miba diamond deposit had considered the stone to be too bulky to be diamond bearing and had discarded it. The girl gave the 890-carat rough to her uncle, who sold it to local diamond dealers. The diamond has since been displayed in multiple museums.
“The demand and appetite for [extraordinary colored diamonds] continues to grow,” said Quig Bruning, head of jewelry for Sotheby’s Americas. “Steeped in history, the Golden Canary is one of the most exquisite diamonds to ever be discovered, not only for its sheer size and intensity in color, but for its stunning beauty that is sure to captivate collectors around the world.”
Sotheby’s will showcase the diamond on a world tour prior to the auction, with stops in cities including Dubai; Taipei, Taiwan; Geneva; and Hong Kong.
By the end of summer 2021, park guests had found 255 diamonds, including four weighing over one carat. Autumn kicked off with a big surprise for one California couple, when Noreen Wredberg and her husband, of Granite Bay, visited the Crater of Diamonds for the first time.
Wredberg was walking on the north side of a central pathway through the search area on September 23 when she spotted something sparkling on top of the ground. Her find turned out to be the largest of the year, a 4.38-carat diamond about the size of a jellybean, with a pear shape and a lemonade yellow color. Wredberg named her gem after her husband’s kitten, calling it Lucy’s Diamond.
The three most common colors of diamonds found at the Crater are white, brown, and yellow. 248 diamonds registered last year were white (weighing 28.6 carats), 54 were brown (16.67 carats), and 52 were yellow (17.02 carats). Interestingly, all nine of the largest diamonds found last year were yellow or brown in color.
By the end of summer 2021, park guests had found 255 diamonds, including four weighing over one carat. Autumn kicked off with a big surprise for one California couple, when Noreen Wredberg and her husband, of Granite Bay, visited the Crater of Diamonds for the first time.
Wredberg was walking on the north side of a central pathway through the search area on September 23 when she spotted something sparkling on top of the ground. Her find turned out to be the largest of the year, a 4.38-carat diamond about the size of a jellybean, with a pear shape and a lemonade yellow color. Wredberg named her gem after her husband’s kitten, calling it Lucy’s Diamond.
The three most common colors of diamonds found at the Crater are white, brown, and yellow. 248 diamonds registered last year were white (weighing 28.6 carats), 54 were brown (16.67 carats), and 52 were yellow (17.02 carats). Interestingly, all nine of the largest diamonds found last year were yellow or brown in color.
Sotheby’s will offer a fancy-vivid-yellow diamond ring at its New York sale next month, estimating the piece could fetch up to $3 million.
The cut-cornered square step-cut, 73.11-carat, VS2-clarity jewel by Mayfair designer Glenn Spiro, called The Sienna Star, is one of the largest fancy-vivid-yellow diamonds to come to auction, Sotheby’s said Wednesday. The piece is one of the top items at the June 9 Magnificent Jewels sale. The auction will feature jewelry for the “Roaring Twenties 2.0” as people return to the social scene following long lockdowns, Sotheby’s noted.
A private collection of six jewels with a combined estimate of more than $13 million are another headline lot at the New York sale. Those include a necklace by Andrew Clunn, set with 28 oval-shaped diamonds totaling over 168 carats, which carries a high estimate of $3 million, and an emerald-cut, 23.59-carat, D-color, internally flawless, type IIa diamond ring with an upper valuation of $2.8 million.
A Colombian emerald and diamond garland necklace by Harry Winston, estimated at up to $2.5 million, and a 13.02-carat Burmese ruby ring, mounted by Carvin French, with a $2 million high valuation, are also part of the collection. Proceeds from the sale of those six items will be donated to charity.
Additionally, Sotheby’s will showcase a Bulgari ring with a 25.29-carat Kashmir sapphire flanked by diamonds, which it expects will bring in up to $3 million. Meanwhile, a modified square brilliant-cut, 3.75-carat, fancy-intense-pink, VVS1-clarity diamond ring, accented by triangle-shaped and round diamonds, is estimated to fetch up to $2.5 million.
The auction house will present jewels from the collection of philanthropist Margaret Jonsson Rogers, the daughter of Texas Instruments founder and Dallas mayor J. Erik Jonsson, as well as property from the estate of Mary Ethel Weinmann, the daughter of Count and Countess André de Limur, it added.
Sotheby’s will offer a fancy-vivid-yellow diamond ring at its New York sale next month, estimating the piece could fetch up to $3 million.
The cut-cornered square step-cut, 73.11-carat, VS2-clarity jewel by Mayfair designer Glenn Spiro, called The Sienna Star, is one of the largest fancy-vivid-yellow diamonds to come to auction, Sotheby’s said Wednesday. The piece is one of the top items at the June 9 Magnificent Jewels sale. The auction will feature jewelry for the “Roaring Twenties 2.0” as people return to the social scene following long lockdowns, Sotheby’s noted.
A private collection of six jewels with a combined estimate of more than $13 million are another headline lot at the New York sale. Those include a necklace by Andrew Clunn, set with 28 oval-shaped diamonds totaling over 168 carats, which carries a high estimate of $3 million, and an emerald-cut, 23.59-carat, D-color, internally flawless, type IIa diamond ring with an upper valuation of $2.8 million.
A Colombian emerald and diamond garland necklace by Harry Winston, estimated at up to $2.5 million, and a 13.02-carat Burmese ruby ring, mounted by Carvin French, with a $2 million high valuation, are also part of the collection. Proceeds from the sale of those six items will be donated to charity.
Additionally, Sotheby’s will showcase a Bulgari ring with a 25.29-carat Kashmir sapphire flanked by diamonds, which it expects will bring in up to $3 million. Meanwhile, a modified square brilliant-cut, 3.75-carat, fancy-intense-pink, VVS1-clarity diamond ring, accented by triangle-shaped and round diamonds, is estimated to fetch up to $2.5 million.
The auction house will present jewels from the collection of philanthropist Margaret Jonsson Rogers, the daughter of Texas Instruments founder and Dallas mayor J. Erik Jonsson, as well as property from the estate of Mary Ethel Weinmann, the daughter of Count and Countess André de Limur, it added.
A rare 6.70-carat VS1 natural fancy deep yellow diamond from the famous Zimmi mine, in Sierra Leone, could fetch as much as $705,000 at auction.
Canary yellow diamonds from Zimmi can command double the price of other fancy yellows because of their uniquely high color saturation levels. Yellow Zimmi stones over five carats are extremely rare.
This gem will lead the Tiancheng International Jewellery and Jadeite Autumn Auction 2020 in Hong Kong on 28 November.
Also at the sale is a pair of Zimmi natural fancy deep yellow diamond earrings 3.03 carat and 3.01 carat with an estimate of up to $320,000.
The Zimmi mine is in the heart of the rainforest region of Sierra Leone where the Mano river marks the border with Liberia.
Yellow diamonds occur when a single nitrogen atom replaces a carbon atom, absorbing the violet and blue light.
A rare 6.70-carat VS1 natural fancy deep yellow diamond from the famous Zimmi mine, in Sierra Leone, could fetch as much as $705,000 at auction.
Canary yellow diamonds from Zimmi can command double the price of other fancy yellows because of their uniquely high color saturation levels. Yellow Zimmi stones over five carats are extremely rare.
This gem will lead the Tiancheng International Jewellery and Jadeite Autumn Auction 2020 in Hong Kong on 28 November.
Also at the sale is a pair of Zimmi natural fancy deep yellow diamond earrings 3.03 carat and 3.01 carat with an estimate of up to $320,000.
The Zimmi mine is in the heart of the rainforest region of Sierra Leone where the Mano river marks the border with Liberia.
Yellow diamonds occur when a single nitrogen atom replaces a carbon atom, absorbing the violet and blue light.
Western Australia has reduced its diamond royalty rate by a significant 33.3 per cent, a move that has been welcomed by Gibb River Diamonds.
The company’s lobbying has led to the reduction of the state diamond gross royalty rate from 7.5 per cent to 5 per cent.
Gibb River stated that the royalty change was in line with the recommendations of the Mineral Royalty Rate Analysis report.
This was published by the Western Australian Department of State Development and Department of Mines and Petroleum in 2015.
“The board of (Gibb River) believes that the reduction of the diamond royalty will have a very positive effect on the sector and is an extremely helpful step in further (Gibb River’s) aim of becoming a profitable diamond producer in Western Australia,” the company stated in an ASX announcement.
The rate is comparable to the 5 per cent royalty rate applied to Rio Tinto’s Argyle diamond project in Western Australia as of May this year, which was amended from the 7.5 per cent rate in 2006 when Rio Tinto decided to proceed with underground mining.
Gibb River operates the Ellendale diamond project in the West Kimberley, which supplies over 50 per cent of the world’s fancy yellow diamonds every year.
The rare colour had driven United States jeweller Tiffany & Co to ink a six-year deal with Ellendale’s former operator, Kimberley Diamonds, for the supply of the diamonds in the past.
Western Australia has reduced its diamond royalty rate by a significant 33.3 per cent, a move that has been welcomed by Gibb River Diamonds.
The company’s lobbying has led to the reduction of the state diamond gross royalty rate from 7.5 per cent to 5 per cent.
Gibb River stated that the royalty change was in line with the recommendations of the Mineral Royalty Rate Analysis report.
This was published by the Western Australian Department of State Development and Department of Mines and Petroleum in 2015.
“The board of (Gibb River) believes that the reduction of the diamond royalty will have a very positive effect on the sector and is an extremely helpful step in further (Gibb River’s) aim of becoming a profitable diamond producer in Western Australia,” the company stated in an ASX announcement.
The rate is comparable to the 5 per cent royalty rate applied to Rio Tinto’s Argyle diamond project in Western Australia as of May this year, which was amended from the 7.5 per cent rate in 2006 when Rio Tinto decided to proceed with underground mining.
Gibb River operates the Ellendale diamond project in the West Kimberley, which supplies over 50 per cent of the world’s fancy yellow diamonds every year.
The rare colour had driven United States jeweller Tiffany & Co to ink a six-year deal with Ellendale’s former operator, Kimberley Diamonds, for the supply of the diamonds in the past.
A new study by University of Alberta scientists could help guide the search for rare, high-value yellow diamonds in the Canadian North.
The researchers, led by PhD student Mei Yan Lai, examined the chemical makeup of stones recovered from the Chidliak and Ekati mines in Northern Canada to get a better understanding of how they formed.
“Without this research, we wouldn’t know that two separate formation events occurred, and that the second, more recent event is responsible for the yellow colour,” explained U of A diamond geologist Thomas Stachel.
“The more we know about the origin of these potentially high-value diamonds, the better results for diamond exploration and value creation in Northern Canada.”
Lai said they wanted to understand the origin of the yellow colour in the diamonds from the two deposits.
“Canadian yellow diamonds have never been studied spectroscopically in detail. Our results suggest that the cause is the preservation of unstable single nitrogen atoms preserved inside the diamonds,” explained Lai, who conducted this research as part of her master’s studies in the Diamond Exploration Research Training School under the supervision of Stachel.
The research team determined that some yellow diamonds contain colourless cores, meaning that the yellow outer layers crystallized on top of clearer centres. Lai determined that the yellow diamonds crystallized no more than 30,000 years before the kimberlite eruptions that brought them up to Earth’s surface.
“Our analysis shows that the colourless cores in these yellow diamonds are about one billion years older,” Lai said. “In fact, the carbon isotope compositions and nitrogen concentrations of the colourless cores and yellow outer layers are significantly different, suggesting that they formed in at least two distinct events and involved different diamond-forming fluids.”
The researchers said discovering a potential new source of yellow diamonds in the Canadian North is economically significant, as the previous main source of high-quality yellow diamonds, the Ellendale Mine in Western Australia, was recently shut down.
The discovery of colourless cores in some of the yellow diamonds may also be of interest to the jewelry trade, said Lai.
“Occasionally, rough yellow diamonds lose their vibrant yellow colour after being cut and polished—probably because this kind of diamond has a thin layer of yellow overgrowth on top of the geologically older colourless core,” she said.
The project is a collaboration with Dominion Diamond Mines and Peregrine Diamonds Ltd. Part of the analyses were done at the Gemological Institute of America.
The research is supported by a bursary through DERTS, funded by the Natural Sciences and Engineering Research Council of Canada’s Collaborative Research and Training Experience program.
The study, “Yellow Diamonds With Colourless Cores—Evidence for Episodic Diamond Growth Beneath Chidliak and the Ekati Mine, Canada,” was published in Mineralogy and Petrology.
A new study by University of Alberta scientists could help guide the search for rare, high-value yellow diamonds in the Canadian North.
The researchers, led by PhD student Mei Yan Lai, examined the chemical makeup of stones recovered from the Chidliak and Ekati mines in Northern Canada to get a better understanding of how they formed.
“Without this research, we wouldn’t know that two separate formation events occurred, and that the second, more recent event is responsible for the yellow colour,” explained U of A diamond geologist Thomas Stachel.
“The more we know about the origin of these potentially high-value diamonds, the better results for diamond exploration and value creation in Northern Canada.”
Lai said they wanted to understand the origin of the yellow colour in the diamonds from the two deposits.
“Canadian yellow diamonds have never been studied spectroscopically in detail. Our results suggest that the cause is the preservation of unstable single nitrogen atoms preserved inside the diamonds,” explained Lai, who conducted this research as part of her master’s studies in the Diamond Exploration Research Training School under the supervision of Stachel.
The research team determined that some yellow diamonds contain colourless cores, meaning that the yellow outer layers crystallized on top of clearer centres. Lai determined that the yellow diamonds crystallized no more than 30,000 years before the kimberlite eruptions that brought them up to Earth’s surface.
“Our analysis shows that the colourless cores in these yellow diamonds are about one billion years older,” Lai said. “In fact, the carbon isotope compositions and nitrogen concentrations of the colourless cores and yellow outer layers are significantly different, suggesting that they formed in at least two distinct events and involved different diamond-forming fluids.”
The researchers said discovering a potential new source of yellow diamonds in the Canadian North is economically significant, as the previous main source of high-quality yellow diamonds, the Ellendale Mine in Western Australia, was recently shut down.
The discovery of colourless cores in some of the yellow diamonds may also be of interest to the jewelry trade, said Lai.
“Occasionally, rough yellow diamonds lose their vibrant yellow colour after being cut and polished—probably because this kind of diamond has a thin layer of yellow overgrowth on top of the geologically older colourless core,” she said.
The project is a collaboration with Dominion Diamond Mines and Peregrine Diamonds Ltd. Part of the analyses were done at the Gemological Institute of America.
The research is supported by a bursary through DERTS, funded by the Natural Sciences and Engineering Research Council of Canada’s Collaborative Research and Training Experience program.
The study, “Yellow Diamonds With Colourless Cores—Evidence for Episodic Diamond Growth Beneath Chidliak and the Ekati Mine, Canada,” was published in Mineralogy and Petrology.
Gibb River Diamonds has completed a review of the mothballed Ellendale diamond mine in Western Australia that will help it edge closer to a proposed restart.
The independent appraisal, which was completed by which was completed by Independent Diamond Valuers International (IDVI) valued gems from the Ellendale 9 East Lobe at $US750 ($1120) per carat.
This price represents a 20 per cent increase since 2008, largely due to the high number of fancy yellow diamonds unearthed at the West Kimberley-based mine.
With these results, a mine revival is looking ominous for the site, which was closed in 2015.
Last December, Gibb River Diamonds accepted an offer from the Western Australian Government apply for new tenements at the site.
“This review is important as it helps Gibb River Diamonds to make commercial decisions regarding mine planning and development priorities at Ellendale,” the company stated.
“Previous operators had a contract to sell the fancy yellow component of their production to Laurelton Diamonds (the jeweller Tiffany & Co).
“It is uncertain if similar premium prices can be achieved with any future fancy yellow goods.
“However, there is a potential opportunity to capitalise in the uniqueness of these fancy yellow goods to sell above market prices.”
The independent appraisal showed a further 18 per cent increase at the Ellendale 9 deposit to $US559 per carat since 2008.
The Ellendale 4 deposit also experienced an increase in value to $US135 per carat, representing a 5 per cent rise in 12 years.
IDVI uncovered 16 per cent fancy yellow diamonds within the Ellendale East Lobe, compared with 9 per cent in the West Lobe.
Gibb River has affirmed that as this information is based on generic sales data, future sales results could “vary significantly” from those in the report, as no sales have occurred since 2015.
Gibb River Diamonds has completed a review of the mothballed Ellendale diamond mine in Western Australia that will help it edge closer to a proposed restart.
The independent appraisal, which was completed by which was completed by Independent Diamond Valuers International (IDVI) valued gems from the Ellendale 9 East Lobe at $US750 ($1120) per carat.
This price represents a 20 per cent increase since 2008, largely due to the high number of fancy yellow diamonds unearthed at the West Kimberley-based mine.
With these results, a mine revival is looking ominous for the site, which was closed in 2015.
Last December, Gibb River Diamonds accepted an offer from the Western Australian Government apply for new tenements at the site.
“This review is important as it helps Gibb River Diamonds to make commercial decisions regarding mine planning and development priorities at Ellendale,” the company stated.
“Previous operators had a contract to sell the fancy yellow component of their production to Laurelton Diamonds (the jeweller Tiffany & Co).
“It is uncertain if similar premium prices can be achieved with any future fancy yellow goods.
“However, there is a potential opportunity to capitalise in the uniqueness of these fancy yellow goods to sell above market prices.”
The independent appraisal showed a further 18 per cent increase at the Ellendale 9 deposit to $US559 per carat since 2008.
The Ellendale 4 deposit also experienced an increase in value to $US135 per carat, representing a 5 per cent rise in 12 years.
IDVI uncovered 16 per cent fancy yellow diamonds within the Ellendale East Lobe, compared with 9 per cent in the West Lobe.
Gibb River has affirmed that as this information is based on generic sales data, future sales results could “vary significantly” from those in the report, as no sales have occurred since 2015.
