Corundum from Delaware County, Pennsylvania, USA
USA | |
| www.libraries.psu.edu/emsl/guides/X/delaware.htm. |
| Joe Dunleavy (Pers. Comm.) |
Gordon's Mineralogy of Pennsylvania (1922) p. 191 | |
AmMin 24:339 | |
| S.G. Gordon, "Mineralogy of Pennsylvania", 1922, p. 190 |