From Ohio History Central
Mineral specimens are not so nearly widespread in Ohio as are fossil specimens, but many areas of the state produce interesting minerals. Many of the best specimens of mineral crystals from Ohio have come from limestone and dolomite quarries in northwestern Ohio. Unfortunately for the collector, most of these quarries are now closed to collectors because of safety and legal considerations. Always OBTAIN PERMISSION before collecting on private property. The book, Minerals of Ohio, available from the Division of Geological Survey of the Ohio Department of Natural Resources, is an excellent guide to identification, occurrence, and collecting information on minerals in Ohio.