If you want to hold the physical metal, make it easy on yourself! Any U.S. dime, quarter, half dollar or dollar that is dated 1964 or earlier is made of 90% silver. For paper products, hold PSLV for cap gains and SLVO for income.
I'm not a geologist, but from the alternative articles I've read, natural gas will explode sometime between now and 2022.
The play for me is $BOIL and I'm boxing in the current price by selling out of the money calls and selling out of the money puts.
Skip to 37:30 for natural gas analysis.