I think the person meant about finding Gold in the ground! From what I have researched there have been gold deposits found in York county PA. But Gold should be able to be found almost anywhere in PA. Why? There have been several Ice ages and the Glaciers covered most or all of PA at onetime or another and that would have brought some deposits from other areas into the state. Also there may have been natural deposits when the rock was formed many millions of years ago. Then through erosion deposited into the streams and rivers.
Your best bet if you are looking to prospect for Gold in PA or any state, is to find and join a local prospecting club. They will be able to help you in finding locations to find Gold and other minerals and gems. Also Metal Detecting Clubs can also be of assistance, they also prospect for gold and can help you in finding places to search and find gold.