This exceptionally thin chert biface is from Nolan County, Texas.  It dates to the Caddo phase of the Mississippian period, ca. 300-1200 BP.  This artefact is referred to as the ‘Sweetwater Biface’.

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The Sweetwater Biface measures 239.7mm long and 85.7mm wide, with an average thickness of 4.76mm. The edge of the biface thins to as little as 1.59 mm. Some of the large percussion thinning flake scars are over 50mm long and extend obliquely across half the biface’s width. Modern flintknappers have attempted to recreate this biface but have been largely unsuccessful. Most attempts that have achieved this thickness tend to be narrower than the original, and those that match the width tend to be somewhat thicker.

The 3D model was made of an epoxy cast from lithiccastinglab.com.  The artefact is curated by the Museum of Native American History, Bentonville, Arkansas, where it is displayed in a rotating display case.

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The Sweetwater Biface was made during the Caddo phase of the Mississippian period, a time of increasing cultural complexity characterised by the development of a ruling class of religious and political elites, the building of ceremonial mounds in ritual centres, and extensive long-distance trade with other groups in the Mississippian world.  The exceptional thinness and workmanship of this biface suggests that it was a prestige item rather than a utilitarian tool.  It is among the finest example of biface thinning known anywhere in the world.  The flat cross section and nature of the biface thinning scars is reminiscent of the thinning seen on some Gahagan bifaces, also made during the Caddo phase, as well as an exceptional bipointed Caddo biface in the Clarence B. Moore collection at the Smithsonian Museum of the American Indian.  People of the Muscogee Nation continue to carry bifaces like this during girls’ puberty rituals, using them to purify the ground for the young women.  The biface was found on the surface in a dry gully in 1986 during the Sweetwater Rattlesnake Roundup.