Though we prefer digging our gems straight from the soil, we still enjoy sluicing through non native buckets for more "exotic" stones that aren't found locally. Gem Mountain is located in Spruce Pine, North Carolina, and has been in business since 1987. You can purchase salted buckets that are available in many sizes with a large variety of different minerals and gemstones. They have both indoor and outdoor sluicing available, so you won't have to worry about the weather getting in the way. Gem Mountain also provides lapidary services and would be happy to make jewelry from the material found in their buckets. One unique feature they offer is a private guided mine tour. There are two different mines to choose from, and reservations would need to be made ahead of time. They require at least 6 people to set up a tour, and the cost is $100 per adult and $50 for children 11 and under.
We purchased a small bucket that ended up containing lots of small colorful chips but only a few workable specimens. We expect the larger buckets to hold better quality stones but opted to take our small treasures and hit the road.