RAPAPORT... Petra Diamonds’ sales accelerated in the past fiscal year as the market improved and discoveries of high-value stones paid off.Revenue jumped 38% to $406.9 million for the 12 months ending June 30, the miner reported Wednesday. Sales volume rose 37% to 4 million carats.The company, which operates the Cullinan, Finsch and Koffiefontein mines in South Africa, attributed the grow...