The world's highest mines, found in an area known as the Roof of Africa in the tiny nation of Lesotho, hold diamonds that are so prized they go for $2,000 a carat—20 times the world average of $100. But the excavation of these extremely precious gems is dangerous and difficult, with high-altitude winds and temperatures that drop to 30 below zero in craggy areas only reachable through steep and narrow mountain passes, reports the Wall Street Journal. What's more, the yield is low compared to other locations, with Bloomberg citing a recent "drought of large stones," for which Lesotho is known. In spite of the many obstacles, places like the Letseng mine, which is owned by UK-based Gem Diamonds, are gaining more attention.
Letseng alone boasts four of the 20 largest diamonds ever found. "It's a mine that mines a jewelry box," diamond magnate Harry Oppenheimer used to say. "He said it produced the most beautiful of all the diamonds," adds Clifford Elphick, Gem’s chief executive. It's home to Type IIa diamonds, for instance, which are the priciest stones. Gem bought 76% of the mine from the Lesotho government in 2006, while Firestone Diamonds now runs the nearby Liqhobong mine, and sold all 76,000 carats offered at its first auction. A single 37-carat diamond went for more than $1 million. Liqhobong "has raised a lot of eyebrows and very well could result in a recurrence of interest in terms of diamond exploration in Lesotho," says an analyst. (In Hong Kong, one diamond went for $71.2 million.)