Pyrolusite from
USA | |
| Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 167 |
| Mineral collecting in Pennsylvania, 1965 - Lapham & Geyer, pg. 130 |
| Lapham & Geyer, 1965. Mineral Collecting in Pennsylvania |
| The Mineralogy of Pennslvania - 1922 Samual Gordon pg. 216. |
| Dana 6:1069. |