Gem Diamonds was given a Valentine's Day boost as it increased the value of its initial public offering by more than a third, to £550m, after higher-than-expected demand from investors.
The company, which recently discovered the world's 15th biggest diamond, saw its share rise 7% to £10.20 in conditional trading this morning. Full trading starts on Monday.
At £550m, the company will be propelled into the FTSE 250, ranking 218th on its debut.
Gem Diamonds was founded by legendary De Beers chairman Harry Oppenheimer's former right-hand man, Clifford Elphick. It has one producing mine, Letseng, in Lesotho, and four development projects in the Democratic Republic of Congo and one in the Central African Republic.
The Lesotho mine last October produced a 603-carat diamond the size of a tangerine, the biggest diamond discovery in 13 years and the 15th biggest ever. More recently, it discovered a 216-carat gem at the mine.