The International Gemological Institute (IGI) recently analysed the heaviest known rough diamond crystal ever to be grown in a laboratory.

IGI claims to be the world’s largest independent gemological laboratory.

Produced by biotechnology company Meylor Global, the record-setting blue crystal weighs 150.42 carats and measures 28.55 x 28.25 x 22.53 mm.


A second grey crystal weighing 141.58 carats and measuring 28.90 x 28.50 x 20.75 mm, was also analysed by the institute.

These crystals were produced using the HPHT process, which replicates and accelerates natural growth.

Both of them surpass the previous known record of 115 carats established in September 2020, also by Meylor Global.

IGI senior director of education, John Pollard, commented on the milestone: “The acceleration of technology in the lab-grown diamond sector is significant.

“In addition to record-setting weights, they’re type IIb crystals, a semiconducting category associated with diamond-based electronics.

“At IGI we’re seeing new benchmarks from the world’s most advanced producers in jewellery applications and beyond.”

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