South Africa's Rockwell Diamonds sparkles after monster diamond finds

A South African diamond company saw its share price surge nearly 70 per cent this week, when it reported uncovering four large gems weighing more than 100 carats each.

Rockwell Diamonds a mid-tier miner, announced news of the discovery on Tuesday. By Thursday its shares on the Toronto stock exchange were worth 69 per cent more.

The four stones weighed between 116-carats and 168-carats. That means each stone weighs at least 23 grams -- roughly half the weight an egg.

Depending on quality the gems could be worth tens of millions of dollars each.

The stones -- two of which are of "exceptional" quality -- were found in the Middle Orange River of South Africa, a region known for its large and high quality gemstones.

"We have recovered four stones exceeding 100 carats in three weeks," Stephanie Leclercq, Rockwell investor relations executive in South Africa, told AFP.

"We generally expect to recover one or two of those stones in a year so that was quite material," she added.

The company is dual listed on the Johannesburg and Toronto stock exchanges.