Shares of Laureate Education ( LAUR) were among the Nasdaq's winners Friday, climbing 17% after the education company posted second-quarter results that easily topped Wall Street's forecast. Laureate posted earnings from continuing operations of $39.6 million, or 75 cents a share, on revenue of $303.1 million. Analysts polled by Thomson First Call expected earnings of 68 cents a share on revenue of $292.9 million. During the year-earlier quarter, the company earned $31.3 million, or 60 cents a share, on revenue of $227 million. Looking ahead, Laureate sees third-quarter earnings of 19 cents to 21 cents a share, excluding stock-based compensation costs of 2 cents to 3 cents a share. The company predicts revenue of $240 million to $265 million. Analysts project earnings of 21 cents a share, including stock-based compensation costs, and revenue of $247.9 million. The company's shares recently were trading up $6.88 to $47.82. Shares of Amcol International ( ACO) tumbled 18% after the mineral producer posted weaker-than-expected second-quarter results. The company earned $11.9 million, or 39 cents a share, on revenue of $152.7 million. Analysts polled by Thomson First Call expected earnings of 40 cents a share on revenue of $160.2 million. During the year-earlier quarter, the company earned $14.3 million, or 46 cents a share, on revenue of $136.3 million. The results during the year-earlier period included tax refunds that added 15 cents a share to the company's bottom line. Amcol shares were down $4.23 to $19.09. Petroleum Development ( PETD) jumped 19% after the independent energy company agreed to sell some of its undeveloped property for $354 million. The company sold 8,700 acres in Colorado to Marathon Oil ( MRO). "We believe this is a great transaction for both PDC and Marathon," Petroleum Development said. "Marathon acquired a high-quality natural gas prospect with great low-risk development potential, and PDC monetized an asset that the company would not have otherwise developed during the next five years or more." The company plans to use some of the proceeds to buy back up to 10% of its outstanding stock. Shares were trading up $6.56 to $39.88.