Chalcedony from selected localities.
USA | |
| [var: Agate] MacFall, P.M. (1951) Gem Hunter's Guide (1st ed.). Science and Mathematics Publishing Company, 187 pages. |
Tschernich, Rudy, 1992, Zeolites of the World |
USA | |
| [var: Agate] MacFall, P.M. (1951) Gem Hunter's Guide (1st ed.). Science and Mathematics Publishing Company, 187 pages. |
Tschernich, Rudy, 1992, Zeolites of the World |