By Ed Butler, BBC Business Reporter, Kono, Sierra Leone
The rising popularity of lab-grown diamonds has caused a big fall in the price of mined gems, and in West Africa’s Sierra Leone, the country’s biggest diamond mine has now closed. In just the past four years, the retail price of polished natural diamonds has fallen some 40%, the main driver being the rapid growth of the lab-grown diamond industry. These factory-made diamonds, produced from crystallised carbon, are chemically and physically identical to mined diamonds but cost up to 70% less. Manufactured mostly in India and China using HPHT (high pressure high temperature) and CVD (chemical vapour deposition) technologies, the global lab-grown diamond market was valued at $29.5 billion last year and is tipped to grow to $91.9 billion by 2034.
In the Kono diamond region of Sierra Leone — immortalised by Leonardo Di Caprio in the 2006 film Blood Diamonds — Koidu Holdings, the country’s biggest diamond mine, shut last year with the loss of 1,000 jobs. The governor of Kono, Augustine Shekho, says the big fall in natural diamond prices has hit the region hard: “Lower diamond values have reduced earnings for miners, constrained investment, and weakened local economic activity.” In the US, engagement rings with lab-grown stones now account for 61% of all sales, a more than two-fold increase since 2022, with 40% of couples stating it is specifically important that their stone be lab-grown. However, critics note that lab-grown diamonds are hugely energy-intensive, requiring vast amounts of electricity. While De Beers has launched a Gemfair transparency project in Sierra Leone to allow retailers to tell the origin story of every mined diamond, the challenge of making that a compelling sales pitch remains formidable in a market driven by size and price.