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Lab-grown diamonds

Lab-grown stones above 3 ct are far easier to source than a year ago

Growth times for larger lab-grown rough have shortened, and 3 ct-plus polished stones that were scarce a year ago are now routinely available.

Imperial Star Gems trade desk1 min read

Lab-grown stones above 3 ct, hard to source a year ago, are now routinely available in most shapes.

  • Growing larger rough takes longer and has a higher failure rate, which kept 3 ct-plus polished lab-grown stones scarce and inconsistently priced through last year.
  • Improvements in reactor consistency have shortened growth times for larger rough and reduced the share that fail to reach usable size or colour.
  • Pricing at 3 ct and above has fallen further, in percentage terms, than at 1 ct, reflecting the improved supply.

For a large centre stone, lab-grown is now a straightforward option rather than a special order — browse lab-grown stones above 3 ct. The investment-grade vs wear-grade guide covers how to think about size versus resale for a stone this large.

Market commentary drawn from publicly available market data and trade reporting, not investment advice. Prices move; figures are indicative and correct as of the date above.