yellow diamond

Study yields new insight in hunt for rare, valuable yellow diamonds

Yellow diamonds, some with colourless cores

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.

Source: miragenews

Gem Diamonds Unearths 135ct. Yellow

Gem Diamonds has recovered a 135 carat yellow at its Letšeng mine in Lesotho, the third significant colored-diamond discovery at the deposit this year.

The company retrieved the high quality, type I stone on June 21, three months after the mine yielded a similar quality yellow diamond weighing 134 carats. Those discoveries follow a two year gap in the recovery of yellow diamonds weighing more than 100 carats from Letšeng. In June 2017, the miner found a 151.52 carat yellow.

552 Carat Yellow Diamond Is The Largest Ever Found In Canada

Finding exceptionally large diamonds is rare. Finding extra large diamonds in fancy colors is even more rare. As such, the announcement by Dominion Diamond Mines that it has unearthed the largest known diamond ever found in North America is big news. Found in October at the Diavik Diamond Mine in Calgary, Canada, the Canadamark yellow diamond weighs in at 552 carats and beats the previous record (held by the Diavik Foxfire diamond) of 187.7 carats that was also found at the same mine.

Dominion Diamond Mines ULC sources responsibly mined diamonds and owns 40 percent of Diavik. The Diavik Diamond Mine is just shy of 150 miles south of the Arctic Circle in the Northwest Territories of Canada, and has produced several important stones in the past. This newest discovery measures about 1-1/2 inches in diameter and more than 2 inches in height. The color and texture are unique geologically speaking, as such a large and rare yellow diamond doesn’t usually form in the region. According to Dominion Diamond Mines’ release, “Abrasion markings on the stone’s surface attest to the difficult journey it underwent during recovery, and the fact that it remains intact is remarkable.”

The Canadamark(TM) program by Dominion Diamond Mines ensures that all diamonds bearing its logo are rigorously tracked from mine to polished gem in order to offer final consumers full transparency of the supply chain. Once the rough is cut, the diamonds will be certified as Canadamark(TM).

In the case of the previously found Diavik Foxfire diamonds, rather than sell it in the rough, the stone was cut and polished — yielding a 37.87-carat brilliant-cut pear shaped diamond and a 36.80 carat brilliant-cut pear shape. Both of these stones sold recently at a Christie’s auction for $1.3 million. It is expected that Dominion Diamond Mines will take the same approach with the 552-carat Canadamark(TM) yellow diamond. The yield could be several larger sized diamonds that Foxfire, or could be similar sizes but more of them. It is impossible to know, as a rough diamond must be carefully studied before being cut to determine the perfect size and shape of the finished, polished stones that will show off their most beautiful color and brilliance.

Certain other fancy yellow diamonds have made history. In fact, among the world’s largest yellow diamonds is the 439.86 carat light-yellow diamond that was found by DeBeers in 1888 and later cut into a 234.65-carat cushion-cut stone. The Tiffany Yellow Diamond is also one of the largest ever discovered. It weighted 287.42 carats in the rough when it was found in 1878 in the Kimberly Mine in South Africa. It was eventually cut in to the 128.54-carat cushion known a the Tiffany Yellow Diamond.

According to a release issued by Dominion Diamond Mines, Kyle Washington, Chairman, says “This incredible discovery showcases what is truly spectacular about Canadamark diamonds. “The color and texture of the diamond are a unique example of the journey that natural diamonds take from their formation until we unearth them. Our Diavik Mine has produced some of the most beautiful diamonds in the world, and this one certainly tops the list.”

Souce: Forbes

July, 2017February, 2025

A yellow diamond is a coloured diamond characterised by its natural yellow body colour. Yellow must be the predominant colour in the diamond, though it can be modified by other hues, such as green, orange, or brown, which can influence the overall appearance of the stone.

Key Characteristics of Yellow Diamonds
Colour Origin:

The yellow colour in diamonds is primarily caused by the presence of nitrogen atoms within the diamond’s crystal structure. These nitrogen atoms absorb blue light, which results in a yellowish hue. The more nitrogen present, the more intense the yellow colour can become.
This unique characteristic makes yellow diamonds distinct from other coloured diamonds, such as blue diamonds, which gain their colour from the presence of boron.
Colour Variations:

While yellow diamonds are often uniformly yellow, the shade and intensity of the yellow can vary widely. Some may show a subtle, faint yellow, while others exhibit a vibrant, rich yellow that is striking and eye-catching.
The yellow can sometimes be modified by secondary hues. For instance, greenish-yellow diamonds might show a yellow-green tinge, while brownish-yellow diamonds can appear more earthy or muted. These variations in colour can affect the diamond’s overall value and appeal.
Canary Diamonds:

The term “canary diamond” refers to a particularly vivid, intense yellow diamond. These diamonds are much rarer than the more common yellow diamonds, and their colour can range from brilliant lemon yellow to golden hues.
Canary diamonds are highly prized in the market for their bright, vibrant appearance and often fetch higher prices due to their rarity and striking colour.
Rarity and Availability:

Natural yellow diamonds are relatively common compared to some other coloured diamonds, like pink or blue diamonds. However, the intensity and depth of the yellow colour can influence the rarity and desirability of a diamond.
Yellow diamonds are found in several regions around the world, including Africa, Australia, and South America.
Grading Yellow Diamonds:

Like all diamonds, yellow diamonds are graded on a combination of colour, clarity, cut, and carat weight. However, when grading coloured diamonds, the hue, tone, and saturation are the primary focus.
Hue refers to the primary colour of the diamond (in this case, yellow), tone refers to the lightness or darkness of the colour, and saturation measures the intensity of the colour. A high saturation, deep yellow diamond will generally be more valuable than a pale or less saturated one.
The most sought-after yellow diamonds have a vivid yellow hue with high saturation and a pleasing, even colour distribution throughout the stone.
Symbolism and Use:

Yellow diamonds are often associated with happiness, wealth, and success due to their vibrant, sunny appearance. They can also symbolise optimism and joy, making them a popular choice for engagement rings, jewellery, and special gifts.
Due to their striking appearance, yellow diamonds are often used in high-end jewellery, where their bold colour can stand out and create a dramatic effect.
Price and Market Appeal:

The price of yellow diamonds can vary significantly depending on factors like colour intensity, clarity, and size. Vivid yellow diamonds, particularly those with a deep, rich hue, tend to fetch higher prices due to their rarity and the high demand in the luxury market.
However, the relative abundance of yellow diamonds compared to other coloured diamonds like pink or blue means they are often more affordable than rarer varieties.

Yellow diamonds are a beautiful and unique variety of coloured diamonds, with their colour arising from the presence of nitrogen in their crystal structure. While yellow diamonds are relatively common, those with intense yellow hues, such as canary diamonds, are rarer and more valuable. These diamonds are graded based on their hue, tone, and saturation, and are prized for their vivid and radiant appearance. They are a popular choice in fine jewellery, symbolising happiness, wealth, and success, while also offering an affordable yet striking alternative to more expensive coloured diamonds.