A colossal diamond the size of a tennis ball has been sold for $53 million in a private sale to Graff Diamonds of the UK, after failing to sell at a Sotheby’s auction last year.

The seller, Canada's Lucara Diamond Corporation, had recovered the diamond from a mine in Botswana in November 2015 and had hoped to get at least $70 million for the stone at the auction in June last year, but bids did not exceed $61 million.

The 1,109-carat diamond was named Lesedi La Rona, which means "Our Light" in Botswana's Tswana language.

The Lesedi la Rona is said to be the largest rough diamond to be discovered in over a century and the largest rough diamond in existence.

In terms of its size, the rough is exceeded only by the Cullinan Diamond, mined in South Africa in 1905. 

The 3016.75-carat Cullinan Diamond produced nine major diamonds that are part of the historic Crown Jewels of the UK, including the Great Star of Africa – currently the largest top- quality polished diamond in existence, weighing 530.20 carats.

The sale of Lesedi La Rona was announced by Lucara earlier this week.