Cameco stock probably costs too much -- but it's hard to argue with this growth story.Cameco (CCJ 3.90%) stock jumped 4% through 11:50 a.m. ET Thursday despite reporting mixed earnings this morning.Heading into the Q3 report, analysts forecast the uranium mining stock would report $535.8 million in quarterly sales -- a number Cameco beat with a stick, reporting sales of $721 million. That's the good news.The bad news is Cameco was supposed to be very profitable on those sales, earning $0.18 per share. Inste ...