Why Diamond Mining Stocks Demand a Different Playbook

Pick up a diamond miner’s quarterly report expecting the numbers you know from gold mining, and almost nothing will look familiar. Carats recovered. Average realised price per carat. AISC per carat. CPHT grade. The Clara platform. The sightholder system. None of these terms appear anywhere in a gold miner’s management discussion and analysis.

That gap is not cosmetic, and it costs money. Diamond miners respond to luxury goods demand cycles, exceptional stone recoveries, and lab-grown substitution pressure, not to inflation expectations or real interest rates. Apply a gold miner’s mental model to a diamond equity and you will misread both the upside and the downside from the very first line of the report.

The timing makes this worth understanding now. Anglo American is executing a high-profile divestment of its De Beers stake through 2026, and the rough diamond market sits in a multi-year crisis that has drawn more investor attention to the sector than it has seen in years.

Here is what this piece gives you: the metrics that actually determine whether a diamond miner is performing, how to read one of their operating results, which stocks give you access and on which exchanges, and the specific risks that set this sector apart from every other resource equity category.

Why diamond miners do not behave like gold miners

The instinct is understandable. A commodity is a commodity, a mine is a mine, and if you can value one resource producer you can value another. That instinct is wrong here, and the reasons run deeper than surface differences.

The gold vs diamonds comparison extends well beyond pricing mechanics: liquidity profiles, inflation sensitivity, and long-run store-of-value characteristics diverge in ways that affect how each asset class fits within a portfolio allocation framework.

Gold is fungible. One ounce is interchangeable with any other, it trades on transparent real-time exchanges, and a gold miner can be valued on reserve-based net asset value models tied to a visible spot price. Diamonds are the opposite of fungible.

Every stone is individually priced against the 4Cs, and rough diamonds are sold through long-term contract systems, tenders, and sights rather than any centralised market. Price discovery is company-specific. Two miners can report the same carat count and generate wildly different revenue.

That structural difference removes a tool gold investors take for granted: hedging. A gold producer can lock in forward revenue certainty because an ounce delivered next year is identical to one delivered today. A diamond producer cannot meaningfully hedge, because each parcel carries its own unique value that no standardised contract can capture.

The demand drivers diverge just as sharply. Gold miner sentiment tracks inflation and real interest rates. Diamond miner valuations track luxury goods demand cycles, consumer confidence, the health of the Chinese property sector, and US retail spending.

The clearest evidence of how quickly this can turn arrived on 20 February 2026, when Anglo American’s full-year 2025 results recorded a US$2.3 billion pre-tax impairment of De Beers, cutting the unit’s carrying value roughly in half to US$2.3 billion. Cumulative De Beers impairments now total approximately US$6.8 billion. Bloomberg, on the same date, described conditions as “one of the diamond industry’s deepest ever crises.”

Here is what those impairment figures tell you. A gold-style reserve-based NAV model would never have flagged this risk, because the problem was not in the tonnes of ore. The physical reserves are intact. The market those tonnes were meant to be sold into collapsed structurally, and no reserve model captures that.

How downstream integration complicates valuation

For an integrated player, the mine is only part of the story. A meaningful share of enterprise value can sit in downstream brands, retail networks, and marketing operations rather than in the ground.

That forces analysts toward sum-of-the-parts valuation: mining assets, midstream operations, and retail brands each carry different risk profiles and command different valuation multiples. You cannot value the whole with a single mine-level NAV.

For pure-play single-asset producers, the approach shifts again. Analysts combine mine-level discounted cash flow models with scenario-based assumptions for grade and quality mix, and they typically apply liquidity discounts relative to comparable gold producers to reflect thinner trading and demand uncertainty.

The three metrics that determine whether a diamond miner is performing

Once you accept that diamond miners are a different animal, the next question is practical: which numbers actually tell you whether one had a good quarter? There are three you cannot skip, and they only mean something when read together.

Start with the three, each in one line:

• Carats recovered: the physical volume of gem-quality diamonds extracted in the period, equivalent to ounces produced for a gold miner.
• Average realised price per carat: the blended revenue per carat across every stone sold in the period.
• AISC per carat: the all-in sustaining cost of producing each carat.

Now build them up properly. Carats recovered looks like the headline number, and on its own it is nearly useless. A quarter can produce a large carat count made up of small, low-quality stones worth very little, because the quality distribution of what comes out of the ground determines whether those carats are worth a great deal or almost nothing.

That is where average realised price per carat enters. It captures the blended value of every stone sold, and it carries a quirk gold investors never face. A single exceptional stone recovery can distort the figure dramatically upward in one quarter, which makes period-over-period comparison genuinely tricky.

The value of any individual stone comes down to the 4Cs: cut, clarity, colour, and carat weight. This is why realised price per carat varies so widely between mines. Two producers can both report carats recovered and sit in entirely different revenue leagues.

AISC per carat is the cost side, and this one maps cleanly onto the gold miner equivalent. It captures mining, processing, site-level administration, sustaining capital, and royalties, all divided by total carats recovered. It is the comprehensive measure of how efficiently a mine turns ore into saleable diamonds.

Put the revenue and cost together and you reach the destination.

Operating margin per carat The spread between average realised price per carat and AISC per carat. This single number synthesises all three inputs and is the central profitability metric analysts use to judge a diamond miner.

That is why a headline carat recovery figure, quoted without the accompanying price realisation and cost data, is essentially meaningless for assessing whether a diamond miner had a good quarter. You need all three, and you need the margin they produce together. With these in hand, you can open any diamond miner’s report and find the numbers that determine a beat or a miss yourself, without leaning on a broker summary.

Reading reserve quality: CPHT and revenue per tonne processed

For reserve quality, gold uses grams per tonne. Diamonds use CPHT, or carats per hundred tonnes, which measures how many carats sit in each unit of ore. It is the direct grade equivalent.

But CPHT alone can mislead, and this is the important part. It must always be read alongside the estimated average value per carat of the orebody, and the metric that combines both into a single economic productivity figure is revenue per tonne processed.

The Letšeng mine, operated by Gem Diamonds in Lesotho, is the perfect illustration. Its grade is extremely low, yet it consistently produces among the highest average dollar values per carat of any kimberlite pipe globally. Contrast that with Lucara‘s Karowe mine in Botswana, a very different CPHT profile, but economically significant because of its tendency to yield enormous high-value stones. Low grade does not mean low value, and that is exactly why you never read CPHT in isolation.

Where to find diamond mining exposure on global exchanges

Knowing what to look for is one problem. Actually buying it is another, and the access routes are more limited and fragmented than most resource investors expect.

Here is the practical picture by exchange:

• TSX (Toronto): direct access for North American investors, home to Lucara and Mountain Province Diamonds.
• LSE (London): Gem Diamonds and Anglo American trade in pound sterling, introducing currency translation effects for US dollar investors.
• NYSE: no major pure-play diamond producer is listed, a genuine gap for US-based investors.
• Moscow Exchange: where Alrosa trades, effectively closed to Western institutional investors.

The NYSE gap deserves attention because of what it forces. A US-based investor wanting direct diamond exposure has to open access to foreign exchanges or accept diluted, indirect exposure through Anglo American ADRs, which bundle diamonds inside a much larger diversified miner.

The Anglo American position is itself in flux. Anglo holds an 85% stake in De Beers and is in advanced discussions to sell it to the Global Diamond Consortium, led by former De Beers CEO Gareth Penny, at a reported value of about US$1 billion, structured as US$750 million upfront and US$250 million deferred. Anglo CEO Duncan Wanblad confirmed the process was in its final stages in late July 2026. As of mid-September 2026, no transaction has closed and De Beers remains consolidated within Anglo.

The De Beers divestment process has moved through several distinct phases since Anglo American announced its strategic review, with ownership structure negotiations, valuation disagreements, and host-government interests each introducing delays that have kept the asset in limbo through mid-2026.

Alrosa sits behind a different wall entirely. The Russian state-controlled producer trades on the Moscow Exchange and is effectively inaccessible to Western institutional investors due to G7 and EU sanctions following Russia’s 2022 invasion of Ukraine. The removal of that supply from Western-accessible markets is a structural reduction that could indirectly support pricing for non-Russian producers.

Two structural features are worth knowing before you buy. Mountain Province Diamonds holds a 49% joint venture interest in the Gahcho Kué mine in Canada’s Northwest Territories, with De Beers Canada operating the remaining 51%, and it independently markets its share of production rather than routing it through the sightholder system. Lucara, meanwhile, runs its Clara digital sales platform, which uses data analytics to match individual rough diamonds directly with downstream polishers, bypassing traditional tenders and sights.

De Beers itself gives you the current market benchmark. First-half 2026 revenue fell to US$1.6 billion, down from US$2 billion in H1 2025, and full-year 2026 production guidance sits at 21-26 million carats.

Pure-play diamond miners are predominantly small- to mid-cap equities with modest trading volumes, wider bid-ask spreads, and higher sensitivity to retail flows. For most global investors, meaningful exposure requires deliberate position sizing and exchange-specific account access, not just a stock screener search.

The structural risks that make diamond miners a distinct risk category

The risks here are not a disclaimer checklist. They compound. Each one is more serious because of the others, and by the end of this you should understand why diamond miners demand a different risk tolerance than diversified resource equities.

The five that matter:

• Lab-grown displacement
• Single-asset concentration
• Country and currency exposure
• No royalty or streaming vehicles
• The Kimberley Process ESG gap

Lab-grown displacement leads because it is structural, not cyclical. Lab-grown diamonds are produced through CVD (chemical vapour deposition) or HPHT (high pressure, high temperature) processes, and the supply is highly scalable and low-cost. That has functioned as a structural cap on natural diamond prices, hitting smaller goods and lower-value commercial qualities hardest, and it permanently shrinks the addressable market for natural stones.

The lab-grown diamond economics driving this structural pressure are more nuanced than a simple cost curve story: CVD and HPHT production yields have improved significantly, retail price points for lab-grown goods have compressed toward commodity levels, and the differential impact across stone size categories has reshaped which natural goods retain pricing power.

Single-asset concentration stacks on top of that. Lucara, Gem Diamonds, and Mountain Province each derive almost all their equity value from one mine. When a period passes without an exceptional stone recovery, the market can be materially disappointed, because a single mine’s geological performance is the whole story.

Country and currency exposure adds another layer. Operations in Botswana, Lesotho, and the Northwest Territories carry fiscal-regime risk from potential royalty and tax changes, contract-renegotiation risk with host governments, and currency volatility against the US dollar, the pricing currency for rough diamonds.

Then there is what the sector lacks. Gold investors can gain exposure through royalty and streaming companies, a traditionally lower-risk avenue. Diamond mining has never developed a comparable ecosystem, so there is no lower-risk proxy for the sector.

The scale of what happens when these forces combine is visible in the numbers. The approximately US$6.8 billion in cumulative De Beers impairments shows how abruptly value can be destroyed when cyclical and structural risks compound, even with physical reserves untouched. Underneath it all, the midstream cutting and polishing operations concentrated in Surat, India, hold inventory that can amplify or dampen rough price movements independently of consumer demand.

“One of the diamond industry’s deepest ever crises.” Bloomberg, 20 February 2026

The compounding is the point. Lab-grown pressure layered on a cyclical downturn means you cannot treat current rough market weakness as purely cyclical and simply wait for mean reversion. Part of the addressable market for natural diamonds has structurally changed, and that part is not coming back on the cycle.

ESG obligations and the Kimberley Process debate

The Kimberley Process Certification Scheme is the sector’s governance backbone. It is designed to exclude conflict diamonds from the trade, and compliance is mandatory for every producer regardless of jurisdiction.

Beyond that, the operational ESG burden is real. Arid-region water management, land rehabilitation obligations, and local community benefit-sharing are material cost and reputational factors, particularly for operations in Botswana and Lesotho.

The critique matters for your investable universe. Some institutional ESG frameworks consider the Kimberley Process’s current definitions and enforcement mechanisms insufficient for modern standards, which can affect a producer’s eligibility for certain ESG-screened funds and, by extension, the pool of capital available to it.

Making a considered entry into diamond mining equities

You now have the pieces. The question is how to assemble them into a decision, and the honest starting point is that this is not a simple sector to enter well.

The analytical minimum is fixed. The three core metrics, carats recovered, average realised price per carat, and AISC per carat, are the baseline for any position assessment, and they must be read together to produce the operating margin per carat that actually tells you how a miner performed.

Be honest about the environment too. The rough diamond market is in a documented multi-year crisis with both cyclical and structural components. Any position taken today is really a view on whether those two components separate, and on which one recovers faster.

The risk profiles within the sector differ meaningfully. Anglo American offers large-cap, diversified, indirect exposure that could change entirely if the De Beers divestment closes. Lucara and Mountain Province are TSX-listed pure-plays with high operational leverage to stone quality. Gem Diamonds is an LSE-listed single-asset producer acutely sensitive to high-grade stone recoveries.

Diamond mining capital allocation decisions at single-asset producers carry unusually high consequence because the mine is the entire equity story: a capital commitment to underground expansion, as Lucara’s Karowe project illustrates, represents a concentrated bet on long-run grade and stone quality assumptions that no diversification can offset.

Before entering any position, work through this sequence:

1. Identify the exchange and access route for the stock.
2. Pull the three core metrics from the most recent quarterly report.
3. Assess the operating margin per carat and its trend.
4. Evaluate single-asset concentration risk.
5. Size the position to reflect the sector’s liquidity constraints.

Two variables are worth monitoring above all others through the 2026-2027 period: the resolution of De Beers ownership, and the trajectory of lab-grown market share. These are not just corporate headlines. Together they signal whether the natural diamond sector is re-anchoring or continuing to contract, and a position in any diamond miner is implicitly a bet on both.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions. Past performance does not guarantee future results. Financial projections are subject to market conditions and various risk factors.