Chert from South Dakota, USA
USA | |
| KellerLynn, K. (2009) Wind Cave National Park Geologic Resources Inventory Report. Natural |
| Roberts, Willard Lincoln, Rapp, George Jr. (1965) Mineralogy of the Black Hills. Bulletin 18. South Dakota School of Mines and Technology |
| Roberts, Willard Lincoln, Rapp, George Jr. (1965) Mineralogy of the Black Hills. Bulletin 18. South Dakota School of Mines and Technology |
Jay Ellis Ransom,1974, Gems and Minerals of America |