Franco-Nevada (NYSE: FNV) has made a name for itself by focusing on streaming deals with precious metals miners, and the company has successfully built up a lucrative portfolio that is highly concentrated on gold streaming deals. Yet in search of new avenues for growth, Franco-Nevada recently said it sees gold as being largely played out, and it wants to look elsewhere for better opportunities. Before it does so, though, Franco-Nevada should look closely at how Freeport-McMoRan (NYSE: FCX) fared in making a similar ill-fated decision.