[2] Like overwhelming majority of geological features in the Highland region, Rainbow Mountain is characterized by sedimentary rocks (mostly limestone) from middle to late Paleozoic filled with fossils of corals and bryozoans.

This is unsurprising, as almost all of contemporary Alabama's landmass was submerged under the Tethys Seaway and served as the ground for splendid coral reef ecosystems.

Local minerals, excluding ones composing aforementioned rocks, are dolomite, calcite, fluorite, and sphalerite.

It would make sense that local people found shelter in the limestone crevices.

The preserve has over three miles of hiking trails, which are managed by the Land Trust of North Alabama.