A small diamond mining company in Lesotho has found a whopping 442-carat diamond. The gem is about the size of a golf ball and is estimated to sell for as much as $18 million. This is not the first large diamond unearthed at the Letšeng mine. Two years ago Gem Diamonds Ltd. found a 910-carat stone, the size of two golf balls, that sold for $40 million.

Considering the rarity of finding such large stones, let’s have a look at what makes the Letšeng mine so special:

Lesotho is a mountainous country and the Letšeng mine is located at an elevation of 3100m (10000ft) - it’s the highest mine in the world. Due to its elevation temperatures at the mine drop to -20C and snowfalls are common in winter, resulting in some of the diamond industry’s toughest and most expensive mining conditions.

Map of Lesotho showing Letseng mine

Aerial view of the Lesotho mine


The Letšeng mine has an extremely low-grade ore producing a yield of only 2 carats (that’s 0.4 grams!) of diamonds for every tonne of ore extracted.

The secret to its success lies in the size and quality of the gems unearthed at the Letšeng mine. Where many mines produce a higher total carat-weight per tonne, the gems are often small and frequently only suitable for industrial use. At Letšeng, the gems are few and far between, but of superior gem quality and size ... and in diamonds size and clarity matters!

422 carat diamond from recent find at Letseng
910 carat Lesotho Legend


Large diamonds over 10 carats (2 grams) are the rarest finds, they command the highest prices per karat, and demand for large diamonds remains strong regardless of economic conditions. The Letšeng mine produces diamonds with an average value per carat of approximately $1600, almost 16 times the industry average. 

Continue reading to find out about some of the stunning diamonds the Letšeng mine has produced over the years and what famous diamond houses have made with them.

  • 910-carat Lesotho Legend (2018) - At 182 grams of exceptional D colour white it is the 5th largest gem-quality diamond ever found. It sold in 2018 for $40 million. We can’t wait to hear what the buyer has in store for this exceptional gem.
  • 603-carat Lesotho Promise (2006) - 121 grams of exceptional D colour white. It sold in 2006 for $12.4 million and was cut into 26 diamonds: 7 pear shapes, 4 emerald cuts, 13 round brilliants, and 1 heart shape. The finished gems total 224 carats or 44.8 grams. All 26 diamonds were fashioned into a single necklace by Graff.
Lesotho Promise
XL Promise necklace by Graff
  • 601-carat Lesotho Brown (1967) - In 1968 Harry Winston cut the 120-gram diamond into 18 diamonds with a total weight of 242.50 carats. The 3rd largest of the gems - a 40.42-carat marquise cut diamond called The Lesotho III - was given to Jackie Kennedy by Aristotle Onassis as her engagement ring. Mounted in platinum by Harry Winston, the ring sold at auction in 1996 for $2,587,500.

Lesotho Brownmarquise cut Lesotho Brown

  • 550-carat Letšeng Star (2011) - The 110 gram diamond was cut into 13 pairs of pear-shaped diamonds, and one 33 carat pear, resulting in over 165 carats of D colour, Flawless clarity gems.
  • 493-carat Letšeng Legacy (2007) - The 98 gram diamond sold for $10.4 million and was later fashioned into 20 polished diamonds.
  • 478-carat Lesedi La Letšeng (2008) - 95 grams of exceptional D colour, Internally flawless rough with potential to yield a 150 carat (30 g) cut stone. Sold to Graff Diamonds in 2008 for $18.4 million. It was fashioned into 11 diamonds, the largest of which was a 102-carat round brilliant diamond. It is the largest round brilliant diamond ever to receive the D colour, Internally Flawless grading from the GIA.

World's largest round brilliant D, IFThe Graff Venus


  • 357-carat Letšeng Dynasty (2015) - The 71 gram diamond sold in 2015 for $19.3 million, it was cut into 23 diamonds by Graff. The principal gem is a 118-carat, D colour, Flawless clarity, heart-shaped diamond called The Graff Venus. It is the largest of its kind in the world.
  • 314-carat Letšeng Destiny (2015) - The 62 gram diamond was cut into 13 diamonds totalling 164 carats of polished diamond. The main stone is a 105-carat, D colour, Flawless clarity, pear-shaped gem called The Graff Vendome.
  • 123-carat Star of Lesotho (2004) - The Star of Lesotho was uncovered just days before the official opening of the mine in 2004. The 24.6 grams gem was sold to Graff Diamonds and fashioned into 53-carat D colour, VVS2 clarity heart-shaped diamond.
    September 01, 2020 — Nicole van der Wolf