Schist from Grand Canyon National Park, Arizona, USA
USA | |
| Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 401. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
www.nps.gov (n.d.) https://www.nps.gov/grca/learn/education/upload/geoarticle-2.pdf |