Billietite from Pennsylvania, USA
USA | |
| Geyer, A.R., Smith, R.C. & Barnes, J.H. (1976) Mineral Collecting in Pennsylvania. |
| Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 56 |
USA | |
| Geyer, A.R., Smith, R.C. & Barnes, J.H. (1976) Mineral Collecting in Pennsylvania. |
| Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 56 |