I had a lot of luck as a kid talking my grandparents into going for a drive in the north GA mountains after a good rain. I would look for recent washouts, or gullies and get them to let me dig through them. I still have a chunk of fools gold about the size of a cantaloupe, and also found a lot...
I have a chunk of pyrite about twice the size of a softball. Fooled many a friend telling them I found it in a creek up by Dahlonaga when I was trout fishing...