AGTA Bans Lab-Grown Diamonds, Gemstones at GemFair

The American Gem Trade Association announced that, starting at Tucson next year, exhibitors will not be allowed to sell lab-grown diamonds or colored gemstones at the AGTA GemFair.

National Jeweler received a news release on AGTA’s decision via email Wednesday morning. The release also was posted on the AGTA website, though it had been removed by Wednesday evening.

AGTA CEO John W. Ford Sr. said the news release was “pulled by error,” and would be reposted today.

According to the release, AGTA’s new rule bans the display of loose gemstones or jewelry “comprising non-natural gemstones, ones that are man-made, synthetic, or lab grown.”

AGTA said its dealers can still sell lab-grown gems if they are disclosed, but only natural gems can be made available for purchase at GemFair.

The association said it enacted the ban to “thwart potential confusion,” confusion it sees happening in the lab-grown diamond industry and fears will affect the colored gemstone industry, even though lab-grown colored stones have been around for more than a century.

When asked what led to the belief that confusion was occurring, or could occur, in the colored gemstone market, Ford said in an email to National Jeweler, “Look no further than the chaos created by synthetics in the diamond industry … Our action is also in response to considerable concerns voiced by AGTA membership in relation to the adverse effects that synthetics could also potentially cause in the colored gemstone industry.”

While the AGTA’s decision has made headlines, it does not seem poised to have a big impact on AGTA GemFair exhibitors, few of whom sell lab-grown gemstones anyway.

In his email, Ford said out of the 260 exhibitors of loose or set gemstones at the 2024 AGTA GemFair Tucson, only two list that they sell synthetic gemstones in the AGTA Source Directory.

“Since sending out over (260) 2025 AGTA GemFair Tucson renewals, we’ve had an overwhelmingly positive response from the vast majority of our exhibitors, greatly outweighing any negative responses,” he said.

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In its news release, AGTA also noted that lab-grown gemstones lack the value inherent to natural gemstones, which are rare and sometimes inimitable.

“AGTA felt that it needed to be crystal clear to buyers that when they attend an AGTA show, they know that they are only shopping mined natural gems from the earth,” said Kimberly Collins, AGTA board president and owner of Kimberly Collins Colored Gems.

“AGTA dealers pride themselves in sourcing superior gems that are rare, beautiful, and natural.”

AGTA also notes that “synthetic gems are not minerals.”

The association said it recognizes two definitions of the word “mineral”—that of the British Geological Survey, defining a mineral as “a naturally occurring substance with distinctive chemical and physical properties, composition, and atomic structure” and that of the U.S. Geological Survey, which defines a mineral as a “naturally occurring inorganic element or compound having an orderly internal structure and characteristic chemical composition, crystal form, and physical properties.”

“The definitions are essentially the same, but the keyword in both that is important is use of the word ‘natural,’” said AGTA board member John Bradshaw.

“It’s important to indicate that synthetic gems are not considered minerals, because minerals are natural, and synthetics are not.”

Source: Nationaljeweler

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

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: DCLA