Market Report: Petra uncovers 'exceptional' 232-carat white stone

Diamond miners sparkled yesterday after Petra uncovered an “exceptional” 232-carat white stone in South Africa.

The diamond is the second largest recovered from Petra’s Cullinan mine, but the company refused to put a price tag on the stone. Canaccord Genuity estimated that it could fetch about $12.5m (£7.8m), with the sale expected in the second half of this year.

News of the find sent Petra surging 15.3p to 192.1p on the mid-cap index, while Gem Diamonds, which has operations in nearby Lesotho, put on 10p to 213p and tiddler Karelian Diamond Resources climbed 0.17p to 1.42p.

Gloom over the Scottish situation continued to depress the blue chip FTSE 100 index, down 5.77 points at 6,829.

Several companies that suffered in the previous session rebounded – Wm Morrison jumped 5.3p to 175.3p, thanks to an endorsement from Citi. The bank believes the supermarket’s dividend is safe for at least the next three years and is hopeful that Morrisons’ price-cutting plan is starting to pay off. Lloyds, up 1.05p at 73.25p, and Barclays, 1p better at 225.9p, were both boosted by HSBC after it argued a rates rise would benefit the pair.

Oxford Instruments gained 35p to 1178p as its chairman Nigel Keen said recent strong momentum of orders means the second half is expected to be even better than normal.

AIM-listed Blur Group, which lets businesses tender contracts online, jumped 5.5p to 86.5p after revealing an eye-popping 303 per cent jump in first-half revenues and a 263 per cent surge in gross profits.

Blur stressed in its update that the most recent figures were calculated using new conservative revenue recognition policies.

Akers Biosciences rocketed 52.5p to 267.5p after announcing an $864,000 contract for sales of its three-minute cholesterol test in Australia, Singapore, UAE and Oman. Its executive chairman, Raymond Akers, said: “This order gives us confidence that this test could become a very important and widely used test worldwide.”

Life science research tool supplier Abcam saw its shares climb 19.75p to 428p, as it revealed a 8.6 per cent rise in full-year revenue.