We all know that precious metals are extremely volatile (high beta) and that commodities usually do not have a long-run real return (zero alpha). I currently have 1% of my portfolio invested in a "Precious Metals & Mining" index fund, which invests in companies that mine precious metals. As user662852 in the comments indicates, investing in the producers of a commodity isn't the same as investing in the commodity; however, their values are correlated. Precious metals are usually successful in market crashes and unsuccessful in market booms.
Is this sector (precious metals and mining) generating comparable returns to the overall stock market over the long run (i.e., around 9% annually)?