According to Mining News Pro - The diamond was recovered from the Letšeng mine, in Lesotho, in which Gem Diamonds holds a 70% stake, in February.
The sale represents a record dollar per carat price of $656 933 for a Letšeng diamond.
http://www.miningnewspro.com/en/News/347108/Gem sells 13 ct pink diamond for $8.7m