The Black Hills in South Dakota. Known for its rocks and precious metals. One big chunk of rock in particular gets most of the attention:
But if Mount Rushmore is the appetizer then the area's rocky main course is in the form various colored, polished stones. You remember going on vacation as a kid and seeing the old prospector stations where you can pick out your own rocks. If they could fit in the tiny pouch then they could be yours (for a semi-reasonable price).
Well those things are back in a big way. Or maybe the never left. But in our estimation, every 20 square feet in South Dakota is required by law to have one. See for yourself:
These things are everywhere. The rocks themselves are fairly worthless but they're pretty and anything that gets people excited about rocks can't be bad.
Just about every tourist attraction also offers the standard sluicing experience too. There are ample opportunities to turn something like this:
Sure, it's not the hardcore, down and dirty rockhounding that veteran gem & mineral collectors are so accustomed to. But for an introduction to the hobby, it's not bad.
So if you are looking for rocks, They're all in South Dakota. Well...maybe not all of them...but, man, those things are everywhere.