Chert from Wyoming, USA
USA | |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| USGS Bull 1391-D |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Fossil Butte Visitor Center Exhibits (2018) National Park Service. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |