Rio Tinto closes Australia's Argyle mine (2020)
After 37 years, Rio Tinto shut Argyle in Western Australia, the world's largest source of pink diamonds. The mine was depleted, not unprofitable, and its closure removed a major supply source from the market.
Argyle pink diamonds became scarce, and their auction prices rose sharply after closure.
Proved that removing a major supply source can support prices — the opposite of what De Beers faces, where demand has shifted to an unlimited lab-grown alternative.
When a diamond mine closes, the market can absorb the loss. The difference here is that demand isn't returning to natural stones — it has moved to synthetic ones.
