This massive dome of Precambrian pink granite covers about 640 acres and rises 425 feet above the bed of Big Sandy Creek.The rock is the best known feature of the Llano Uplift of the Central Mineral Region and it is a National Natural Landmark.The natural area covers almost 1,644 acres and activities such as primitive backpacking, camping,hiking,rock climbing, picnicking,and geological studying are available on site.