What Is an Abrader?

A well used sandstone abrader at Univesity of Iowa Museum of Natural History

Imagine you are walking through a field. A piece of sandstone catches your eye so you lean over and pick it up. The stone, roughly the size of your hand, is covered in deep grooves. What is the strange stone? What caused the elongated depressions? Has it been modified by human hands?

This unusual rock is an abrader, and its history is extensive.

4,000 years ago, in this widespread and misty valley, a tribe of Native American Indians dwell. A woman sews shell beads onto a pair of moccasins. As she works, her needle, which is made from a long bird bone, begins to dull. Eventually, she draws the needle off the sinew she uses as thread. The woman instinctively reaches for a piece of sandstone about the size of her hand. Down the center, a shallow channel runs.

She maneuvers the needle in smooth strokes along the stone until the needle is honed to a fine taper. At this point, the shallow groove in the sandstone has become deeper. Now she can continue sewing efficiently.
Later, a man returns to the settlement from his work. He has spent the whole day hollowing out a canoe with a stone celt. The tool needs to be polished and sharpened, or it will not function properly. He retrieves the grooved stone from it's place in the corner of the wikiup, and sharpens the edge of the celt, further deepening the grooves on the sandstone surface.

Many years pass; tools are sharpened and polished on the abrader hundreds of times. Eventually, the grooves become so deep it cannot be used any longer. The people discard the old tool, where it sits in the field for thousands of years for you to find. 

For more information on ABRADERS

Article by Gwen McDaniel