Supercomputer Cracks Mystery of How To Make “Super-Diamond”

Diamond is one of the hardest materials on Earth, as its super-strong carbon lattice structure makes it incredibly resistant to compression.

Theoretical predictions suggest there is another structural form of carbon out there that could surpass diamond in hardness – the problem is, nobody has ever been able to make it.

Now, simulations performed using the fastest exascale supercomputer in the world are helping researchers better understand the stability of diamond at very high pressures. These simulations are also helping create new potential synthesis methods that could one day see this “super-diamond” become a reality. The research is published in the Journal of Physical Chemistry Letters.

Is BC8 diamond 2.0?
The basis for this hypothetical “super-diamond” is the eight-atom body-centered cubic (BC8) crystal structure. BC8 is a tetragonally bonded structure that packs atoms even more efficiently than the face-centered cubic (FCC) structure of traditional diamond. BC8 phases for both silicon and germanium have been synthesized at high pressures – and successfully recovered to ambient conditions – but the same is not true for carbon.

“The BC8 phase of carbon at ambient conditions would be a new super-hard material that would likely be tougher than diamond,” said senior study author Ivan Oleynik, a physics professor at the University of South Florida (USF).

“The BC8 structure maintains this perfect tetrahedral nearest-neighbor shape, but without the cleavage planes found in the diamond structure,” explained Jon Eggert, study co-author and chief scientist at the Lawrence Livermore National Laboratory (LLNL) High Energy Density Science (HEDS) Center. Eggert agrees with Oleynik that “the BC8 phase of carbon at ambient conditions would likely be much tougher than diamond.”

Theoretical predictions indicate that a BC8 phase of carbon is possible – and that it would be around 30% more resistant to compression than diamond – but so far scientists have been unable to produce it in a lab.

One step closer to lab-grown super-diamond
For this new study, the team was able to carry out multi-million atomic molecular dynamics simulations on Frontier, the fastest exascale supercomputer in the world. These simulations were designed to investigate the extreme metastability of diamond at very high pressures, in conditions that well-exceeded its known range of thermodynamic stability.

This new research was possible thanks to the recent development of very accurate machine learning models for interatomic potentials. These simulations can describe interactions between individual atoms with unprecedented accuracy, even when considering very high-pressure and high-temperature systems.

“By efficiently implementing this potential on GPU-based (graphics processing unit) Frontier, we can now accurately simulate the time evolution of billions of carbon atoms under extreme conditions at experimental time and length scales,” Oleynik said. “We predicted that the post-diamond BC8 phase would be experimentally accessible only within a narrow high-pressure, high-temperature region of the carbon phase diagram.”

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The simulation showed that, at pressures above 10 million atmospheres and temperatures above 4000 Kelvin, the BC8 carbon phase is the most stable form of carbon.

The significance of this is two-fold, the researchers explain. Firstly, this explains the previous failed attempts to synthesize the elusive BC8 phase of carbon seeing as it is only stable under a very narrow range of temperatures and pressures. But it also allows for further predictions of viable compression pathways that might make BC8 synthesis achievable.

Based on their simulations, the research team has proposed a double-shock compression pathway for BC8 synthesis, which is currently being explored in further experiments at the LLNL’s National Ignition Facility. Their ultimate goal is to be able to synthesize a small amount of this BC8 “super-diamond” and then find a way to recover a seed crystal of the material back to ambient conditions.

Super-diamond could already be hiding in distant exoplanets
Investigating the properties of “super-diamond” is important, not just because scientists love it when there is a mystery to solve.

Astrophysical observations have discovered a number of carbon-rich exoplanets beyond our solar system. The ultra-high pressures in the interior of these planets may be enough to form diamond as well as the BC8 phase of carbon, the researchers believe.

“Consequently, the extreme conditions prevailing within these carbon-rich exoplanets may give rise to structural forms of carbon such as diamond and BC8,” Oleynik said. “Therefore, an in-depth understanding of the properties of the BC8 carbon phase becomes critical for the development of accurate interior models of these exoplanets.”

Reference: Nguyen-Cong K, Willman JT, Gonzalez JM, et al. Extreme metastability of diamond and its transformation to the BC8 post-diamond phase of carbon. J Phys Chem Lett. 2024

Source: technologynetworks

How Flawed Diamonds Got Their Mojo Back

Prices of round, lower-clarity diamonds have performed better this year than their higher-clarity counterparts, as is clear from this graph showing the trend for 1-carat, D to H polished goods. Stones with SI clarity in those categories rose 5% for the period from January 1 to March 12, compared with a 2.2% increase for VS. VVSs slipped 0.4%, while prices of internally flawless (IF) goods fell 3.1%. The figures from RapNet reflect asking prices. Prices of fancies were down for the same period due to high inventories.

This is a correction from the situation in 2023, when prices of round, 1-carat, D to H, SI stones slumped 33% for the full year as consumers shifted from flawed naturals to eye-clean synthetics. The category has regained only some of that ground. Still, the improvement during those nearly two-and-a-half months has been considerable. Why has this happened, and why have higher clarities performed less strongly?

1. What goes down (faster) must come up (faster).

Having lost a third of their value in 2023, SI diamonds had more potential for a base effect going into 2024. By contrast, prices of round, 1-carat, D to H, VS diamonds fell 23% last year, with VVS and IF for the same range both falling 20%.

2. Lab-grown

The improvement in SIs reflects reduced pressure from lab-grown. Competition from synthetics is still there, but the impact appears to be easing. This is partly because price declines for lab-grown at retail have made them feel like less of a luxury product to consumers and damaged their appeal among jewelers. Retailers have the power to guide consumers toward whichever product gives them the most profit.

Last year, the damage to the lower-clarity segment in natural came largely from the fact that consumers could buy a lab-grown diamond with a higher color and clarity for the same or less money. SIs can have visible flaws if you pick the wrong one.

“The customers who wanted natural VS2 plus were never going to buy lab-grown,” said Ari Jain, chief financial officer at New York-based wholesaler House of Diamonds.

3. Impact of price decline and stabilization

Connected to the first two reasons is the fact that severe declines in prices of natural SIs in 2023 have made the category more affordable and therefore more popular for consumers. Jewelers, however, have a different consideration: The price stabilization for natural stones in the past few months has encouraged those who were investing in lab-grown to return to the mined product.

“Prices have come down over the course of 2023 to a place that made natural more attractive,” said Andrew Rickard, vice president of operations at Rochester-based wholesaler RDI Diamonds. “As they’re reverting back to natural, SIs still becomes the economic place to enter.”

4. High-end brands not buying

Many top luxury brands are not buying diamonds at the moment, several market sources observed. This inevitably affects the IF to VVS categories, the preferred clarities for these high-end houses.

The reason could be the state of consumer demand, especially in China, where purchasers lean toward higher clarities than in the US. One of the more compelling explanations is that high-end houses stocked up in 2023 because of concerns that a Group of Seven (G7) ban on Russian diamonds would raise prices of non-Russian production. They later realized that finding the right diamonds with confirmed origin was easier than they expected and are in no rush to add to their inventories.

Source: Rapaport

Brilliant Earth Reports Record Revenue for 2023

Brilliant Earth’s sales grew 4% year on year to $124.3 million in the fourth quarter amid a record number of orders.

The 18% increase in individual orders offset a 12% decline in the average value per sale during the three months that ended December 31, the retailer said last week. Net profit for the period fell 69% to $1.9 million.

Engagement rings were one of the top sellers for the company, with demand for those above $10,000 increasing year-on-year in the fourth quarter, Brilliant Earth CEO Beth Gerstein said last week in an earnings call, transcribed by Seeking Alpha. The average sales price for engagement rings was up 4% year-on-year during the three months.

Additionally, new campaigns featuring celebrities and influencers brought in consumers. The launch of Brilliant Earth’s Sol collection, in partnership with Emmy-nominated actress Camilla Morrone, proved popular, with productivity “far outpacing” that of prior collection launches, Gerstein explained. The company’s new lab-grown Capture collection, made with synthetic diamonds manufactured using 100% renewable energy, also “resonated strongly” with consumers, it said.

For the full-year, sales rose 1.5% to $446.4 million, while net profit dropped 75% to $4.7 million.

Brilliant Earth expects sales for the first quarter of 2024 to reach between $96.5 million and $98.5 million, ranging from a decrease of 1% to growth of 1%, chief financial officer Jeff Kuo noted on the earnings call. For the full year, net sales are anticipated to rise 2% to 5% to between $455 million and $469 million.

Source: rapaport

Russian diamond ban creates costly delays, Antwerp diamond dealers say

Antwerp’s diamond dealers face long and costly delays following an EU ban on Russian-origin diamonds that took effect on March 1 and has slowed imports, they say in a letter seen by Reuters.

The letter, dated March 13, said the disruptions would erode the competitive advantage of the centuries-old Antwerp diamond trade. It was addressed to Belgium’s main diamond industry group, Antwerp World Diamond Centre (AWDC), and requested a review of the new procedures.

Any impact is likely to be reduced by sluggish market conditions. Diamond inventories are high and prices have fallen. Paul Zimnisky, a global diamond analyst, said last month that prices were down 25% from their early 2022 peak.

Al Cook, CEO of mining company Anglo American’s De Beers’ diamond business, has said the miner would reduce production this year in response to surplus supply.

“While we fully support the decisions taken by Belgium, the European Union, and the G7 nations, in regards to the sanctions of January 1st 2024, the implementation of the measures to enforce the sanction has adversely affected all of our operations,” said the letter, signed by over 100 local firms.

“The intention was to prevent the flow of diamonds from sanctioned states, but the reality we face is the severe disruption of our supply chains, and alienation from the rest of the global trade.”

A Belgian government official said the delays were temporary and were easing.

The EU and Group of Seven (G7) countries agreed to ban direct imports of Russian diamonds to their markets as of Jan. 1 and before phasing in a full ban on Russian-origin stones via third countries from March 1 because of Moscow’s war in Ukraine.

Russia’s state-run Alrosa, which together with De Beers is one of the world’s top diamond producers, was also placed under sanctions by the EU.

Diamond hub
Antwerp remains the world’s biggest diamond hub though 90% of stones are polished in India. Belgium pushed hard for the G7 to adopt a version of its proposed plan to try to prevent Antwerp from losing more business after major Western jewellers began eschewing Russian stones.

Diamond dealers said their shipments have been held up for over a week at customs even if the gems were straight from African producers.

The Belgian government official said shipments pending would be processed within 24 hours.

“The indirect ban coincided with the Hong Kong Diamond Fair which is an annual peak period… This, in combination with the expected teething problems caused some initial delay in processing of shipments during the first days,” he said.

Diamond dealers say they expect more problems when the additional tracing requirements take effect from September.

“We see the procedures will cause Antwerp to further lose competitive advantage… rather than deal a meaningful blow to any sanctioned products,” the letter said.

“The current trajectory threatens the existence of Antwerp’s diamond industry, a heritage of six centuries.”

The head of the AWDC, Ari Epstein, said the group would soon present the new measures, adding it was “acutely aware of the challenges and disruptions this timing may have caused”.

“Let me be unequivocally clear: the violation of sanctions is criminal in nature and not taken lightly by governments or our organization. Our commitment to compliance… is unwavering and absolute,” Epstein said in a statement.

Source: Dmitry Zhdannikov and Julia Payne mining.com

Anglo reports latest De Beers’ rough diamond sales value

Anglo American has announced the value of rough diamond sales (Global Sightholder Sales and Auctions) for De Beers’ second sales cycle of 2024, amounting to US$430 million.

The provisional rough diamond sales figure quoted for Cycle 2 represents the expected sales value for the period and remains subject to adjustment based on final completed sales.

Al Cook, CEO of De Beers, said: “I’m pleased to see a further increase in demand for De Beers rough diamonds during the second sales cycle of 2024. However, ongoing economic uncertainty in the US has led to retailers restocking conservatively after the 2023 holiday season. Consumer demand for diamond jewellery is growing in India but remains sluggish in China. Overall, we expect that the ongoing recovery in rough diamond demand will be gradual as we move through the year.”

Source: globalminingreview

Jewelry Segment Sees Rebound in Recovering China Luxury Market

Jewelry was one of the strongest categories as China’s luxury market expanded in 2023 following the resurgence of tourism, according to a new report by Bain & Co.

The jewelry segment increased between 15% and 20% last year after the government lifted Covid-19 restrictions and travel resumed, Bain said last week. The fashion and lifestyle category also gained 15% to 20%, leather goods 10% to 15%, and beauty 8%. The watch market saw the softest rebound, up 5% to 10%.

While the growth was strong in 2023 compared to the previous year, which saw sharp declines due to restrictions on travel and extended lockdowns, it has still not returned to the record high of 2021. That disparity is primarily attributable to lower consumer confidence, a slower-than-expected economic recovery, and the return of Chinese consumers to purchasing luxury goods overseas.

Overall, China’s personal luxury sales rose 12% in 2023, Bain noted. The market is set to see mid-single-digit growth in 2024. Part of the issue with the slower market recovery is the pricing gaps between luxury goods in China and other markets. Jewelry is as much as 10% higher on the mainland than overseas, while watches cost up to 5% more.

Source: Rapaport

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US Sanctions Zimbabwe President for Diamond Smuggling

The US has sanctioned Zimbabwe President Emmerson Mnangagwa for corruption in connection with gold and diamond smuggling, as well as human-rights abuses.

The Treasury Department’s Office of Foreign Assets Control (OFAC) accused Mnangagwa of “providing a protective shield” to gold- and diamond-smuggling networks that operate in Zimbabwe, it said last week. He is also accused of directing Zimbabwean officials to “facilitate the sale of gold and diamonds in illicit markets” and taking “bribes in exchange for his services.”

The US has also restricted Mnangagwa for being a leader or official of entity, including any government entity, that has “engaged in, or whose members have engaged in, serious human-rights abuses,” OFAC explained.

“The Zimbabwe president is a foreign person who is a current or former government official, or a person acting for or on behalf of such an official, who is responsible for or complicit in, or has directly or indirectly engaged in, corruption, including the misappropriation of state assets, the expropriation of private assets for personal gain, corruption related to government contracts or the extraction of natural resources, or bribery,” OFAC stated.

OFAC issued the new sanctions after US President Joe Biden signed an executive order that terminated Zimbabwe’s national emergency and revoked sanctions on the entire country, so as not to target its citizens.

“The US remains deeply concerned about democratic backsliding, human-rights abuses, and government corruption in Zimbabwe,” said Wally Adeyemo, deputy secretary of the treasury. “The changes we are making today are intended to make clear what has always been true: Our sanctions are not intended to target the people of Zimbabwe. Today we are refocusing our sanctions on clear and specific targets.”

Source: Rapaport

17ct. Diamond to Head Up Christie’s New York Sale

The pear brilliant-cut, D-color, VVS2-clarity, type IIa stone is the lead item in the Jewels Online auction, which will take place from March 11 to 21, Christie’s said Wednesday. This will be the auction house’s first jewelry sale of the year, and will feature a curated selection of signed jewels, diamonds and colored gemstones. Select pieces from the sale will be open for public viewing at the Christie’s showroom in Rockefeller Center.

The auction will include items by well-known design houses such as Cartier, Hemmerle, Tiffany & Co., and Van Cleef & Arpels. Also up for sale will be a private collection from philanthropist and sailing enthusiast George Frederick “Fritz” Jewett, Jr. and his wife Lucy.

Two charitable collections will be on the block as well: One to benefit the Public Broadcasting System (PBS) Foundation, and another belonging to interior designer, author and Oprah Winfrey Show guest Nate Berkus. Proceeds from the latter will go toward financial aid at New York’s Grace Church School.

Here are some of the other highlights from the sale:

This ring features a round brilliant-cut, 1.13-carat, fancy-blue, VS2 diamond center stone with baguette-cut sapphires and diamonds on either side. It has a high estimate of $250,000.
A ring with a cut-cornered rectangular modified brilliant-cut, 8.21-carat, fancy-intense-yellow, VS1-clarity diamond is expected to bring in up to $100,000. The lot has no reserve price.
Christie’s will auction this Van Cleef & Arpels necklace featuring pink tourmalines, onyx and diamonds for an estimated $60,000 to $80,000.
This coin and bicolor-gold Tubogas bangle bracelet by Bulgari carries an estimate of up to $80,000. The cuff contains three staters from the ancient city of Corinth, each depicting a Pegasus on one side and the head of the goddess Athena on the other.

Source: Rapaport

215 carat Rough Diamond is Biggest in Liqhobong’s History

Firestone Diamonds is in the process of selling the largest diamond ever recovered from its Liqhobong mine, in Lesotho.

The 215 carat stone is being put to a competitive bidding tender process, with viewings in Antwerp and Dubai.

“This sale represents another milestone in our ongoing efforts to deliver value to stakeholders,” said Firestone in a statement today (6 March).

Liqhobong, located 2,600 meters above sea level in the highlands of Lesotho, began production in 2017.

The mine closed in October 2022 for two-and-a-half years in response to a lockdown imposed by South Africa, which surrounds the landlocked kingdom.

UK-based Firestone reported Q4 revenue last year of $12.6m, down almost 40 per cent on the previous quarter.

Source: Idex

Lucapa Diamonds recovers two diamonds of over 100 ct

Lucapa Diamond Company and its partners Endiama and Rosas and Petalas, have recovered two diamonds of over 100 ct each from the terraces of Mining Block 46 at the Lulo mine, in Angola.

The miner plans to offer the first, a 162.42 carat, type IIa diamond, as part of its normal run-of-mine sales later this month, it said Tuesday. It will sell a 116.14 carat rough, which it discovered the next day, by tender at a future date, along with other high-value, type IIa diamonds the company unearthed from the deposit recently.

Both diamonds were recovered in February, with a 162 ct diamond recovered first, and a 116 ct diamond recovered the following day.

The 116 ct Type IIa diamond will be sold through a tender at a future date, along with other high-value Type IIa diamonds recovered recently, while the 162 ct diamond will be sold as part of normal run-of-mine sales later this month.

Lucapa has assets in Africa and Australia, with interests in the Lulo diamond mine and the Mothae diamond mine, in Lesotho.