London - It’s a rock for the ages.

A 3-billion-year-old diamond the size of a tennis ball — the largest discovered in over a century — could sell for more than $70 million, auctioneer Sotheby’s said Wednesday.

The auction house plans to offer the Lesedi la Rona diamond in London on June 29.

The diamond was unearthed in November in Botswana at a mine owned by Canada’s Lucara Diamond Corporation. It measured 1,109 carats, the second-largest gem-quality rough diamond ever discovered. Its name means “our light” in the Tswana language of southern Africa.... Read More: VIN