Feldspar Group from selected localities.
USA | |
| [var: Perthite] |
| [var: Perthite] Barton, W. & C. E. Goldsmith (1968) New England Beryllium investigations. US Bureau Mines RI 7070 |
USA | |
| [var: Perthite] |
| [var: Perthite] Barton, W. & C. E. Goldsmith (1968) New England Beryllium investigations. US Bureau Mines RI 7070 |