Lots of old abandoned mines (and working mines) in Mt. Ida area, west of Hot Springs. You can go to some of the working mines and pay a daily fee, then keep what you find!
Most of the quality sites are leased up already but you can find scattered "good stuff" if you do your research. Heck, there are even some small crystals on my farm west of the city, looks like sugar stuck to rocks.
They once mined silver between Hot Springs and Mt. Ida. The community is called "Old Silver". Catchy name.
Good luck,
Bob in Arkansas