Rio's diamond unit fades to $118 million as Diavik winds down

First-half diamond sales fell 27% to $118 million and output dropped 51% to 1.1 million carats after Diavik's March closure. The unit swung to a $72 million EBITDA loss as Rio counts down its last diamond mine.

By The Rough Desk29 July 2026Brief 35 sec · Full read 2 min

PLATE IThe number

$118M

H1 sales

A mine being emptied

H1 2025 Sales$162M

H1 2026 Sales$118M

Source Rio Tinto diamonds, H1

What changed

Rio Tinto's diamond business is now a wind-down with a revenue line. First-half sales fell twenty-seven percent to $118 million, rough-diamond output dropped fifty-one percent to 1.1 million carats, and the unit swung to an underlying EBITDA loss of $72 million from a $55 million loss a year earlier.

What it means · The Desk’s View

Rio's fade is a preview of the supply cliff the natural-diamond story leans on — mines are closing faster than new ones open, and the majors are not rushing to replace them. That is bullish for scarcity and bruising for anyone who needs steady rough today, and the gap between those two truths is where the next few years of pricing get decided.

The article3 sections · 192 words

Table I · A mine being emptied

	Figure
H1 2025 Sales	$162M
H1 2026 Sales	$118M

Rio Tinto diamond unit. H1 sales, US$ millions (2026 down 27%). Carat Capital graphics desk. CC/2026/147

IA wind-down with a revenue line

These are the numbers of a mine being emptied, not run.

Diavik, in Canada's Northwest Territories, closed in March after reaching the end of its ore life, and Rio is processing the last of its stockpiled material through at least the end of 2026.

With Argyle shut since 2020, Diavik was the miner's final diamond asset; when the stockpile is gone, one of the world's major producers exits the business entirely.

IIThe expensive tail

The tail is expensive. Rio expects to spend roughly $1 billion over the coming years on closure and rehabilitation across Diavik, Argyle and its other legacy sites — the unglamorous back half of mining that arrives long after the last carat is sold.

A diamond unit that once anchored supply from the far north now shows up mainly as a remediation bill.

IIIA supply cliff, previewed

For the wider market the exit tightens an already thinning supply of natural rough at the top and middle. Diavik's better goods fed a specific appetite for Canadian-origin, conflict-free stones, and that provenance does not transfer to another mine.

As Diavik and its peers close without like-for-like replacements, the scarcity argument that Gem Diamonds is monetizing at the high end gets structurally stronger.