From Ohio History Central
Human Hand Effigy, Hopewell Culture, Hopewell Mound Group, Ross Co., A 283/000294
The native peoples of Ohio may have begun to use mica during the Early Woodland period, but its use in the crafting of ceremonial objects became especially important during the Middle Woodland period.
Mica is a shiny mineral that occurs in layers, which can be split apart into thin, translucent sheets. Sometimes called isenglass, plates of mica have been used historically as windows for stoves.
Hopewell culture spiritual leaders used small slabs of mica for a kind of mirror, possibly used in divination ceremonies, and artisans cut sheets into a variety of delicate shapes that may have been sewn onto garments to serve as personal ornaments.
Mica does not occur naturally in Ohio. Its source is in the Appalachian Mountains of North and South Carolina. Ohio's Hopewell people may have obtained the mica in trade with the Middle Woodland cultures in this region, or perhaps pilgrims brought offerings of mica and other rare and precious materials to the great earthwork centers of southern Ohio.
Mica continued to be used by some Late Woodland cultures in Ohio, but only in much smaller quantities and these later peoples did not cut it into the elegant effigies so characteristic of the Hopewell culture.
- Lepper, Bradley T. Ohio Archaeology: An Illustrated Chronicle of Ohio's Ancient American Indian Cultures. Wilmington, Ohio, Orange Frazer Press, 2005.