Almost every show cave you will ever walk through is limestone. This one is gypsum, and it is the largest natural gypsum cave in the world open to the public.
The gypsum here is mostly in the form of alabaster, the soft translucent stone carvers have used for thousands of years, and it comes in more than one colour. There is white and there is pink, and there is black alabaster, which occurs in only three veins anywhere on Earth: one in Oklahoma, one in Italy and one in China. You are standing in one of the three. The cave also carries selenite, another form of gypsum, in clear crystal formations through the rock.
The raw material was laid down over 200 million years ago in the Permian, when an inland sea covered this part of North America. The sea evaporated and left enormous mineral deposits behind, later upheavals lifted the gypsum bed close to the surface, and running water then tunnelled the caverns through it. Gypsum dissolves far faster than limestone, which is why caves like this are rare: they tend not to last.
The park covers 200 acres about four and a half miles south of Freedom, Oklahoma, near State Highway 50. There is no official record of who found the cave. Oklahoma considered closing the park for budget reasons in 2017; it stayed open, and it remains open daily.
Guided tours run through the main cave on a lit route with stairs, and the park also offers wild caving in undeveloped caves nearby, which is unusual for a state park. Bats use the caverns, so expect rules about gear worn in other caves.
Other places on the map within a couple of hours.
