Petra Diamonds Slumps After Dearth of Big Gems at Cullinan Mine

Petra Diamonds Ltd. sank the most in almost two months in London after saying annual sales would be short of market expectations on a dearth of large gems at its main mine.

Petra dropped as much as 10 percent, the steepest intraday slide since April 16, and was at 153.9 pence by 8:14 a.m. in London.

It recovered a “lower incidence of high-quality stones and higher volumes of smaller diamonds” in South Africa, Petra said in a statement Friday. It expects annual sales of $430 million, compared with an average analyst estimate of $447.3 million. Petra retained its output target of 3.2 million carats.