The gemstone went to an unnamed telephone bidder. The auction was held online by Sotheby's in Hong Kong due to the pandemic.
The diamond was taken from a 271-carat stone which was discovered at a Canadian mine in 2018.
Only seven other diamonds larger than 100 carats and of the same quality have gone under the hammer.
The stone did not have a reserve price - a minimum price that the seller is willing to accept for an item.
It is the first time in history that a diamond has sold at auction this way.