New method could simplify detection of diamond deposits

Geologists from ETH Zurich and the University of Melbourne have established a link between diamond occurrence and the mineral olivine.

In a paper published in the journal Nature Communications, the scientists explain that their method will simplify the detection of diamond deposits. The process relies on the chemical composition of kimberlites, which occur only on very old continental blocks that have remained geologically unchanged for billions of years, predominantly in Canada, South America, central and southern Africa, Australia and Siberia.

According to the study’s lead author, Andrea Giuliani, olivine is a mineral that makes up around half of kimberlite rock and consists of varying proportions of magnesium and iron. The more iron olivine contains, the less magnesium it has and vice versa.

“In rock samples where the olivine was very rich in iron, there were no diamonds or only very few,” Giuliani, who has been studying the formation and occurrence of the gemstones since 2015, said in a media statement. “We started to collect more samples and data, and we always got the same result.”

His investigations ultimately confirmed that olivine’s iron-to-magnesium ratio is directly related to the diamond content of the kimberlite. Giuliani and his team took these findings back to De Beers, who had provided them with the kimberlite samples. The company was interested and provided the scientific study with financial support and asked the researchers not to publish the results for the time being.

A slow, repetitive process
In 2019, Giuliani moved from Melbourne to ETH Zurich and, supported by the Swiss National Science Foundation, began to look for explanations for the connection between olivine’s magnesium and iron content and the presence of diamonds.

With his new colleagues, he examined how the process of metasomatism, which takes place in the earth’s interior, affects diamonds. In metasomatism, hot liquids and melts attack the rock. The minerals present in the rock react with the substances dissolved in the fluids to form other minerals.

The geologists analyzed kimberlite samples that contained olivines with a high iron content—and hence no diamonds. They discovered that olivine becomes richer in iron in the places where melt penetrates the lithospheric mantle and changes the composition of mantle rocks significantly. And it is precisely in this layer, at a depth of around 150 kilometres, that diamonds are present.

The infiltration of the melt that makes olivine richer in iron destroys diamonds. If, on the other hand, no or only a small amount of melt from underlying layers penetrates the lithospheric mantle and thus no metasomatism takes place, the olivine contains more magnesium—and the diamonds are preserved.

“Our study shows that diamonds remain intact only when kimberlites entrain mantle fragments on their way up that haven’t extensively interacted with previous melt,” Giuliani said.

A key point is that kimberlites don’t normally reach the earth’s surface in one go. Rather, they begin to rise as a liquid mass, pick up fragments of the mantle on the way, cool down and then get stuck. In the next wave, more melt swells up from the depths, entrains components of the cooled mantle, rises higher, cools, and gets stuck. This process can happen multiple times.

“It’s a real stop-and-go process of melting, ascent and solidification. And that has a destructive effect on diamonds,” Giuliani noted. If, on the other hand, conditions prevail that allow kimberlites to rise directly to the surface, then this is ideal for the preservation of the gemstones.

De Beers is already using olivine analysis
Olivine analysis is as reliable as previous prospecting methods, which are mainly based on the minerals clinopyroxene and garnet. However, the new method is easier and faster: it takes only a few analyses to get an idea of whether a given kimberlite field has diamonds or not.

“The great thing about this new method is not only that it’s simpler, but also that it finally allows us to understand why the previous methods worked,” Giuliani said. “De Beers is already using this new method.”

Source: mining.com

Botswana Assigns $65M for Stake in Belgian Manufacturer

Botswana has designated BWP 890 million ($65 million) from its new fiscal 2024-2025 budget for the purchase of a 24% stake in Belgian manufacturer HB Antwerp.

The deal, which it first announced in March, calls for the African country to supply rough from state-owned Okavango Diamond Company (ODC) to HB Botswana for five years. The partnership would operate in a similar fashion to HB’s previous supply deal with Lucara Diamond Corp, enabling Botswana to retain a share of the polished profits.

Lucara terminated its rough-supply agreement with HB in September, citing a “material breach of financial commitments” by the Belgian manufacturer as the reason for the split. That decision came on the heels of HB’s departure from cofounder and managing partner Oded Mansori, whom it has since reinstated to his original role.

There was media speculation late last year that the Botswana government was pressuring Lucara to reconnect with HB, and that the split could affect Botswana’s interest in the manufacturer. Lucara owns the Karowe mine in Botswana. The miner has since announced that it planned to form new supply deals with other vendors.

Source: Diamonds.net

De Beers Rough Prices Slip 6% in 2023

De Beers’ prices fell last year as a prolonged oversupply in the midstream and economic challenges weighed on demand.

The company’s rough-price index, which reflects like-for-like values, dropped 6% for the 12-month period, parent company Anglo American reported Thursday.

Sales volume slipped 19% to 27.4 million carats, with the average selling price sliding 25% to $147 per carat. While the company has not published its full-year revenue, rough sales decreased 36% to $3.63 billion, according to data from De Beers’ 10 sight reports for 2023.

Output for the year was down 8% to 31.9 million carats as the company transitioned its Venetia deposit in South Africa to underground mining and processed lower-grade ore from its Canadian and Namibian sites, outweighing an increase in Botswana.

In the fourth quarter, sales volume plunged 63% year on year to 2.7 million carats, while production declined 3% to 7.9 million carats.

“De Beers offered full flexibility for rough-diamond allocations…as sightholders continued to take a cautious approach to their purchasing during the quarter as a result of the prevailing market conditions and extended cutting and polishing factory closures in India,” the company noted. “De Beers was loss-making in the second half of 2023 owing to the subdued sight sale results, reflecting conditions of cyclical lows driven by the prevailing macroeconomic environment. Whilst there has been some improvement coming into 2024, the prospects for economic growth remain uncertain and it may take some time for rough-diamond demand to fully recover.”

The miner expects to produce between 29 million and 32 million carats in 2024. However, it has cautioned that it “will assess options to reduce production in response to prevailing market conditions.”

Source: Rapaport

The Moussaieff Red Diamond

One of the most famous red diamonds from Brazil is “The Moussaieff Red” which was discovered by a Brazilian miner named Ze Tatu in the state of Minas Gerais.

It is a 5.11 carat, Internally Flawless, Fancy Red diamond which weighed 13.90 carats in the rough — a true treasure from the Brazilian diamond legacy.

De Beers Debuts Online Rough Tenders

De Beers has introduced a new online “sealed bid” tender for some of its rough diamonds.

The Offer, which went live last week, allows buyers to key in the price they’re prepared to pay for a lot, unseen by other bidders.

It is an additional sales channel rather than a replacement for the online auctions that have been taking place since 2008.

Online auctions have accounted for the 10 per cent of De Beers production that is not sold at Sights.

“We are constantly looking at new ways for customers to source natural diamond supply with a view to make the experience as simple and flexible as possible while keeping commerciality in mind,” said Rhyzard Bilimoria, account director in De Beers Group Diamond Trading.

“We believe that for certain product ranges and during certain industry conditions, the Offer represents the most effective channel to meet customer and industry needs.”

He said the Offer was quick, simple, confidential and allowed buyers to bid any amount.

“We recognise that in periods when trading conditions are evolving, different customers can perceive different value depending on their specific activities – it is therefore beneficial to implement a sales process where there is no visibility of other bidders’ activity, as this supports customers’ ability to make independent assessments of value that reflect their own underlying demand.”

De Beers cancelled its online auctions in the last two sales cycles of 2023 amid slow demand.

Source: IDEX

De Beers Slashed Rough Prices. Will Polished Suffer?

On Monday, De Beers’ customers turned up at the first day of the miner’s January sight to find rough prices were down by an average of 10% to 15%. The reductions were more drastic than many had predicted.

The drops ranged from slight adjustments for the more in-demand smalls, all the way to an estimated 20% to 25% cut for 2- to 4-carat, lower-clarity rough, sources said.

Sightholders usually celebrate a price decrease, since their margins can be thin at the best of times. But, immediately, the industry started asking the obvious question: Will this cause polished prices to fall?

The basic assumption is that cheaper raw materials mean cheaper end products. Yet the situation with diamonds is more complicated.

First, there are different ways of pricing polished. You can sell based on the current cost of replacing the goods — a method that would imply polished prices should fall, since De Beers rough is now cheaper. However, it’s also possible to price according to the input cost, with the vendor aiming for a certain profit based on how much the rough actually cost. This would, in theory, mean the latest drop in rough prices would not impact polished until around March, when the new, cheaper material enters the market as polished.

Still, most sightholders that spoke to Rapaport News this week don’t expect polished prices to suffer — though the people who buy their polished might disagree. The miner’s move, sightholders argue, was merely an adjustment to polished-price levels and to the price of rough at open tenders and auctions.

De Beers had priced its goods some 15% higher than the rest of the rough market, as it chose to sell less volume since August rather than discounting during the market slump. Its last significant price decrease before this was in July 2023. Since the start of that month, the RapNet Diamond Index (RAPI™) for 1-carat diamonds has fallen 12.5%.

Price drops at De Beers are not always in sync with the market. In recent years, the company has held off reducing prices until crises have eased, as it did in 2020 following the first round of Covid-19 lockdowns. De Beers sold just $216 million in rough at its last two trading sessions of 2023 as it followed this policy amid weak demand.

But the company needs revenue after incurring a loss in the second half of last year. It appears to have chosen the market improvement as an opportune time to stimulate sales.

“In the final quarter of 2023, we saw some stabilization in polished prices, including a number of areas of natural polished now starting to see some price increases,” a De Beers spokesperson said in a statement Wednesday. “Following this stabilization, we have realigned our rough-diamond trading activities, in terms of prices, volumes and supply flexibility, to reflect prevailing industry conditions.”

With the market in flux, De Beers also showed sightholders sample assortments of rough diamonds that indicated the types of goods and prices customers can expect for this year. Based on these so-called “to see” boxes, sightholders were able to apply for additional goods if their need for rough has increased since they submitted their supply applications in mid-December, the spokesperson explained.

However, market participants expect total sales at the sight of $300 million to $400 million — low for January, which is usually a time of post-holiday restocking. The recent season in the US was okay, but Chinese demand remains slow.

Whether sightholders maintain this cautious approach — and De Beers doesn’t sell too much — will be crucial. Excessive buying could lead to a repeat of last year’s oversupply, which ended with India’s two-month voluntary freeze on rough imports. During the recent crisis, De Beers continued selling — albeit at lower volumes — even when competitor Alrosa canceled sales.

At the January sight, De Beers also removed the extra concessions that had allowed sightholders to refuse goods in the final sights of last year without being penalized. The end of this flexibility increases the danger that goods will flood the market and that manufacturers will sell polished cheap to increase cash flow and raise money for rough.

The fact that De Beers diamonds remain relatively expensive could itself support polished prices, since sightholders have no room to offer further discounts.

“There’s no hooray if you look at those prices,” said one sightholder, noting that even the new rates will probably enable businesses to break even rather than turn a significant profit. “It’s just aligning with [reality]. It’s not like you’re going to make 10% [profit].”

Another sightholder agreed the reductions didn’t go far enough — but believed it would likely be up to the trade to drum up polished demand rather than expect further cuts to rough prices.

“If anybody thinks this is a price reduction — no, it’s a halfway correction, and not even achieving the final goal,” he asserted. “But I also believe they won’t do much [in terms of price cuts] after this. I think their expectation is: ‘Listen, we got you 60% of the way. The other 40%, you guys have to jump up now.’”

Source: Diamonds.net

De Beers Cuts Rough Prices by Average of 10% to 15%

De Beers reduced rough-diamond prices by an average of 10% to 15% at this week’s sight, aiming to stimulate sales and bring its rates more in line with the rest of the market, sources told Rapaport News.

The miner lowered prices by 5% to 10% for rough under 0.75 carats, with thinner or no reductions for the smallest items that produce melee, sightholders and other market insiders said Monday on condition of anonymity.

Rough weighing 0.75 to 2 carats saw reductions of approximately 10% to 15% on average, while prices of 2-carat and larger goods dropped about 15%, the sources added.

Select makeables — the 2- to 4-carat rough stones that produce SI2 to I2 diamonds — fell more sharply, with estimates ranging from 20% to 25%. This reflects the impact of lab-grown competition on mid-market US demand in the past year, sightholders explained. De Beers does not comment on pricing.

De Beers tends to sell less volume during a downturn and reduce prices only once the polished market has improved. The RapNet Diamond Index (RAPI™) for 1-carat diamonds slid 21% in 2023, the worst year on record for the category, but sightholders reported a moderate uptick in US demand since the holiday shopping season began, though Chinese orders remain weak.

The global market also stabilized as a result of India’s two-month voluntary freeze on rough imports, which ended December 15.

“[In the past, De Beers] didn’t want to change prices because they didn’t know [what the state of the] polished [market] was,” one of the sources commented. “They have an idea where polished is now, and have adjusted rough to polished.”

However, several sightholders said the drops did not go far enough, with De Beers’ prices still above those of outside tenders and auctions and also too high for many manufacturers to make a profit.

Even with the price reduction, the sources expected demand at the sight to be limited, with sales of around $300 million. The trading session, De Beers’ first of the year, began Monday and runs through Friday in Gaborone, Botswana.

Source: Diamonds.net

De Beers approves $1 billion spending at Botswana mine

Global diamond giant De Beers said it will go ahead with a planned $1 billion investment to extend the life of its flagship Jwaneng mine in Botswana, even as last year’s downturn in gem demand persists.

The Anglo American (AAL.L) unit and the Botswana government, which jointly own Debswana Diamond Company, have approved the spending that will convert the Jwaneng pit into an underground operation.

Debswana said in 2018 it planned an investment to extend the lifespan of the mine by 11 years from 2024. De Beers said the spending is necessary as long-term supply of rough gems is expected to tighten.

Angola last year started mining at its new Luele project, the biggest in the country and one of the world’s largest by estimated resources, despite depressed diamond demand.

“The global supply of natural diamonds is falling, so moving forward with the Jwaneng underground project creates new value for investors,” De Beers CEO Al Cook said.

Demand for rough diamonds has been weak in recent months with India – cutter and polisher of 90% of the world’s rough diamonds – asking global miners to stop selling it gemstones to manage accumulated stocks.

“This investment is aligned with our strategy to prioritise investments in the highest quality projects,” Cook said.

De Beers last year agreed a new diamond sales pact, which will see the government’s share of diamonds from the Debswana joint venture gradually increase to 50% over the next decade.

Source: Reuters

Bruce Cleaver Steps Down from De Beers Boards

Bruce Cleaver will leave his role as cochair of De Beers’ board of directors and will also relinquish his position on the board of the miner’s lab-grown diamond-manufacturing company, Element Six.

The move follows Cleaver’s exit as CEO in early 2023 after six years in the position. Cleaver’s appointment to the boards was to enable a smooth transition of leadership to his replacement, Al Cook, a De Beers spokesperson told Rapaport News.

Additionally, while on the board, “Bruce also supported the finalization of the commercial negotiations with the government of the Republic of Botswana,” the spokesperson said. “With the leadership transition complete, and with De Beers and Botswana having signed heads of terms for the new agreements, Bruce has delivered on those objectives, and so has stepped down from the board of directors.”

Cleaver will remain with De Beers in an advisory capacity, the spokesperson added. Duncan Wanblad, CEO of De Beers parent company Anglo American, will now be sole chair of the miner’s board of directors.

Source: Diamonds.net

US Polished Imports Fall in October

US polished-diamond imports dropped 21% to $1.5 billion in October, recording a fifth consecutive year-on-year decline, according to recent data from the US Commerce Department. The decrease reflected a fall in the volume of imports as well as a lower average price. Polished imports have not seen a year-on-year rise since May, when the timing of the JCK Las Vegas show prompted an 18% increase.

Source: US Commerce Department data; Rapaport archives.

About the data: The US, the world’s largest diamond retail market, is a net importer of polished. As such, net polished imports — representing polished imports minus polished exports — will usually be a positive number. Net rough imports — calculated as rough imports minus rough exports — will also generally be in surplus. The nation has no operational diamond mines but has a manufacturing sector, so it normally ships more rough in than out. The net diamond account is total rough and polished imports minus total exports. It is the US’s diamond trade balance, and shows the added value the nation creates by importing — and ultimately consuming — diamonds.

Source: Diamonds.net