Modest diamond found in Finland

The idea of diamond discoveries in Finland might seem far-fetched. However, since the early 1980s, kimberlite rocks have been discovered in Finland. These rocks contain the sparkling and much sought-after gem.


“Kimberlites are ancient, usually small and very rare volcanic rocks, which millions of years ago erupted to the surface from a depth of 200 to 300 kilometres,” says Marjaleena Lehtonen, M.Sc.


In her doctoral dissertation in the field of geology, she studies the diamond potential of Finnish rock, while simultaneously searching for new ways of locating diamond deposits.


So far, discoveries in Finland include about two dozen kimberlite deposits, each measuring a few hectares. According to Lehtonen, their diamond content is modest compared with the deposits in the world’s leading diamond-producing countries, such as Canada and South Africa.


However, the quality of diamonds discovered in Finland meets the requirements for jewellery, and Lehtonen says there is a possibility of discovering a financially viable diamond deposit.


“Eastern and Northern Finland are part of the same bedrock area that stretches to the Archangel region in Russia, which is home to world-class diamond deposits.”


So far, the largest diamond discovered in Finland measures 5 mm in diameter and weighs 1.2 carats.


Although the diamond content of the kimberlite deposits thus far discovered in Finland is low, the country’s good infrastructure attracts prospectors. The good road network, for instance, significantly reduces the total costs of prospecting.


Discovering new kimberlites is not, however, easy, as they are often overlain by dozens of metres of soil. Nevertheless, Lehtonen’s study gives new hope to gemstone hunters. It revealed what accompanying minerals are found near kimberlite deposits. A new deposit was also located in Kaavi during the study.