Historical Marker
The Professors' Monument
Historical marker location:
913 South University Avenue, Ann Arbor, Michigan
( Marker can be reached from South University Avenue north of Tappan Avenue, on the left when traveling east.)
Marker installed: 1996
Michigan is the only state to have two designated "state stones": the Petoskey Stone, which is the state stone of Michigan, and the Isle Royale Greenstone, which is the state gemstone of Michigan. The Petoskey Stone is a fossilized coral that is found primarily in the northern Lower Peninsula, while the Isle Royale Greenstone is a rare mineral found only on Isle Royale in Lake Superior.