Chert from Illinois-Kentucky Fluorspar District, USA
USA | |
| Mineralogical Record (1997) 28, 3-49. |
| Mineralogical Record (1997) 28:3-49 USGS Professional Paper 36 |
| USGS Professional Paper 36 |
| Collected by A.G. |
Gems and Minerals of America - Jay Ellis Ransom-1974 |
Commodore Mine, Crittenden County, Kentucky, USA