Focus on: Diamonds, as 2,492-Carat Stone Found in Botswana

Recently, the second-largest diamond ever found – a 2,492-carat stone – was unearthed at Karowe mine in Botswana owned by Canadian firm Lucara Diamond.

It is the biggest find since the 3,106-carat Cullinan diamond, found in South Africa in 1905. That was cut into nine stones, many of which are in the British Crown Jewels.

Botswana is one of the world's biggest producer of diamonds, accounting for about 20% of global production

The diamond was detected with the use of Lucara's Mega Diamond Recovery X-ray technology, said Mr Lamb.

In light of the discovery, here we take a closer look at the global diamond mining industry. 

How are diamonds formed and mined?

Diamonds form deep within the Earth's mantle under conditions of extreme heat and pressure, resulting in the formation of diamond crystals. This process typically occurs at depths of 150km or more, where temperatures exceed 1,000 Celsius and pressures surpass 50 kilobars. Most diamonds are between 1 and 3.5 billion years old.

Diamond mining involves extracting diamond-bearing rock (kimberlite) from the Earth's crust. Two primary methods are employed: open-pit mining and underground mining. 

Open pit diamond mining is more common than underground mining because diamond deposits are found close to the Earth's surface. Open pit mining allows for the use of larger equipment and can extract greater volumes of material, which results in higher productivity and lower costs per carat of diamond recovered.

In Russia, both methods are employed extensively, with the country boasting some of the world's largest open pit diamond mines, including the iconic Mir mine. It also has significant underground operations, like the Internationalaya mine.

South Africa is renowned for its deep underground mines, including the Cullinan and Finsch operations, while in Canada's northern territories, open pit mining dominates, with mines like Diavik and Ekati being examples. 

There is a third method: alluvial diamond mining, which involves extracting diamonds from riverbeds and coastal areas, with Angola being a leading nation on this front. 

How are mined diamonds processed?

Once extracted, diamond-bearing ore undergoes several processing stages. The ore is crushed and then separated using various methods, including dense media separation, X-ray sorting, and hand sorting. Rough diamonds are then classified based on size, shape, quality, and potential use. For gem-quality diamonds, the next steps involve planning, cutting, and polishing to create finished stones. Industrial diamonds may undergo different processes depending on their intended application.

What are the industrial uses of diamonds?

In manufacturing, diamond-tipped tools are used for cutting, grinding, and drilling hard materials. The electronics industry use diamond components in high-power semiconductor devices. 

In healthcare, diamond scalpels are employed for delicate surgical procedures, and they are also used in optical components, wear-resistant coatings, and high-pressure scientific experiments.

The jewellery industry has traditionally relied on natural diamonds, but synthetic diamonds are gaining market share. But natural diamonds – valued for their rarity, age and emotional significance – continue to dominate the high-end market. 

Which countries are the leading diamond miners?

Russia, Botswana, and Canada are the top diamond-producing countries by value. Russia, through companies like Alrosa, is the world's largest producer by volume. Botswana, in partnership with De Beers, is a significant source of high-quality diamonds. Canada has emerged as a major producer in recent decades, with several large mines in operation. Other notable producers include Angola, South Africa, and Namibia.

Leading consumers of mined diamonds?

The US is the world's largest consumer of diamond jewellery, with China and India both seeing rapid growth in diamond consumption, driven by expanding middle classes and changing cultural attitudes towards diamond jewellery. Japan and Europe are also substantial markets for diamond jewellery. 

The industrial diamond market is more evenly distributed globally, with demand closely tied to manufacturing and technological development in various countries.

Which companies are the largest miners of diamonds?

De Beers has historically been dominant in the diamond industry and remains a major player, operating mines in Botswana, Namibia, South Africa, and Canada. Alrosa, the Russian state-controlled company, is the world's largest diamond producer by volume. 

Other significant diamond mining companies include Rio Tinto, which operates mines in Australia and Canada, and Petra Diamonds, with operations primarily in Africa.