Can I deduct a loss that I took when I sold physical gold and silver to an individual?

It depends. 

1. You can report a loss on  property held for investment purposes if it was sold at a loss.  You will want to keep the receipts for the gold and silver you sold and the proof of sales price.
2. If this was personal property such as jewelry, then a personal loss is not be allowed against other income.

Reporting the sale of gold or silver would be reported as a collectible:

Go to Wages & Income

1. Scroll to Investments 
2. Select Stocks, Bonds, Mutual Funds (1099-B)
3. Answer Yes to "Did you sell any Investments? Answer No to "Did you get a 1099-B or brokerage statement?"
4. Enter the information about your sales - Select the holding period > Select Collectible as the Type
   1. Long term: held more than one year (one year plus one day)
   2. Short term: held one year or less
5. After you enter information about the sale: Description, Date sold, Date acquired, Sales proceeds, Cost or other basis, Click Continue
6. Any of these less common items for this sale? Put a check in the third line for Proceeds from collectibles

Note: If a collectible is sold, any gain would have a 28% maximum rate.