There is a small quaint once-jail-now-museum called Franklin Gem and Mineral Museum in Franklin, North Carolina chock full of different rocks and crystals, as well as educational materials. It is run by volunteers and makes a wonderful visit if you are ever in the area. Outdoors is a small sand area where kids (or adults) can dig for their own rocks as well. We also stopped at Jackson Hole Gem Mine to find some raw gems, but we had much more fun at the Franklin Gem Museum, which was free(!).
Different rocks and crystals under UV light at the Franklin Gem Museum.
Mining for treasures under water
Amethyst, aventurine, citrine, quartz, moon stone, garnet, topaz