RAPAPORT... Petra Diamonds recovered two gem-quality rough stones fromits Cullinan mine in South Africa Friday. The 100.83-carat, D-color, type IIstone and another 6.12-carat, blue, type II diamond will be included in the company'supcoming tender later this month. Petra's stock price rose 6% on the day of the announcement. The company's share performance has been suffering partly due to sluggish prices at Cullinan, with the stock price down about 50% since a year ago. Last month,Juan Kemp, general manager of Cullinan, told Reuters he lay awake at nightwondering when the mine would yield its next big stone. Image: The 100.83-carat white diamond. (Petra Diamonds)