Weathering pyritiferous phyllites form water-soluble oxalates and sulphates protected by an overhang. Collecting at the locality (within a National Park) is not freely allowed. Unauthorized collecting may result in Federal prosecution.
Ref.: - Flohr, M.J.K., Dillenburg, R.G., and Plumlee, G.S. (1995): Characterization of secondary minerals formed as the result of weathering of the Anakeesta Formation, Alum Cave, Great Smoky Mountains National Park, Tennessee: USGS Open File Report #95-477, 24 p.
- Coskren, T. D. & Lauf, R. J. (2000): The Minerals of Alum Cave Bluff, Great Smoky Mountains, Tennessee. Mineralogical Record, 31, 163-175.
- American Mineralogist (2000): 85: 1561.
- http://www.uwm.edu/Course/geosci697-tectonic/GroupD/AlumCave/AlumCaveBluffs.html