Material Insights · Understanding the Material World

Diamonds

Diamonds are two markets: natural gems sold on rarity and branding, and synthetic industrial grit that cuts, drills and polishes.

Precious metals · No. 26

  • Not on a critical list
  • HHI 2,032 · moderately concentrated
Precious metals · Foundation · Matter

Over 99% of the world's industrial diamond is made in factories, and most gems are cut in India.

Chart: Illustration: Diamonds

Where it comes from

Chart: Map of where it comes from

Natural diamonds form deep in the mantle and rise in kimberlite pipes, or wash into river and sea gravels as in Namibia and Angola. Most ore holds only a few carats per ton.

Three things to know
  1. A diamond's value rests on the four Cs: carat, colour, clarity and cut; small grade changes can multiply price per carat.
  2. US gemstone imports fell 44% in 2025, from $19.6 billion to about $11 billion.
  3. Diamond conducts heat better than any other bulk material, which is why it is used in heat spreaders.
The journey
  1. 1 Kimberlite pipeOr gravels, up to about 6 ct/t
  2. 2 RecoveryCrushed, dense-media separation, X-ray sorting
  3. 3 Rough saleSorted and sold at sights or tenders
  4. 4 CuttingPolished, mostly in India
  5. 5 JewellerySet and sold at retail
Covered in What makes something a commodityCommoditiesSupply, demand and the cost curveCommoditiesPrices and cyclesCommoditiesHow commodities tradeCommoditiesHow commodities moveCommodities
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