Rising commodities are lifting stocks, but not profits. That could be a problem

Commodity prices have been rallying over the past six weeks, but the share prices of major metals producers now face a couple of significant hurdles: high valuations and a challenging earnings season. First Quantum Minerals Ltd. FM-T and Freeport-McMoRan Inc. FCX-N are set to report their quarterly financial results on April 23. Teck Resources Ltd. will report its results on April 25, with Cameco Corp. CCO-T and Ivanhoe Mines Ltd. IVN-T reporting on April 30. Normally, these might not be riveting events for investors if commodity prices were relatively steady over the prior three months. This time, though, prices for…