Agate from selected localities.
USA | |
| MacFall, P.M. (1951) Gem Hunter's Guide (1st ed.). Science and Mathematics Publishing Company, 187 pages. |
| Mineralogy of Michigan (2004) Heinrich & Robinson |
USA | |
| MacFall, P.M. (1951) Gem Hunter's Guide (1st ed.). Science and Mathematics Publishing Company, 187 pages. |
| Mineralogy of Michigan (2004) Heinrich & Robinson |