The highlight of the 200-acre Alabaster Caverns State Park is the cavern formed of alabaster, a rare form of gypsum, making it the largest natural gypsum cave in the world that is open to the public and the only gypsum show cave in the United States. Daily guided tours of Alabaster Cavern leave promptly on the hour from 9am-4pm. For safety reasons, a maximum of 40 visitors are allowed on each tour. A fee is charged for the tour. The cavern tour includes interpretation by a guide and a well-lit path. Group tour rates are available for school and youth groups only and only after a reservation has been made and a confirmation number been issued. Group reservations are required at least two weeks in advance by calling the park office.