The biggest thing to hit Bethel in years, this well-designed geology museum is still a work in progress (but should be open by the time you read this) but a preview gallery and store are open in the meantime. The goal is to collect, preserve and share outstanding gems and minerals (including meteorites), with an emphasis on Maine specimens and mining in the state (the western region has a great reputation for rock hounds). The museum has acquired some excellent private collections to exhibit.
The preview gallery (open 10am to 5pm, Monday through Saturday) is free to visit.