Gem Diamonds (LON:GEMD) said it received US$13.5mln from the sale of two exceptional plus 160 carat (ct) rough diamonds recovered from the Letšeng mine at the end of January.
The 162.02ct type II diamond sold for US$11.1mln and the 161.31ct type I sold for US$2.4mln.
Gem Diamonds owns 70% of the Letšeng mine in Lesotho.
Shares in Gem Diamonds have risen 17% so far this year and other diamond producers, including Stellar Diamonds (LON:STEL), have also staged a comeback amid higher prices for rough diamonds and a general resurgence in mining stocks.