Material · lithic
Upper Mercer chert
North America — Eastern Woodlands
Upper Mercer chert is the black to blue-grey chert of Coshocton and adjacent counties, Ohio, the second great Ohio toolstone after Flint Ridge and the material of most Turkey-tail blades and many Adena and Archaic points. It was quarried from bedrock and stream cobbles. Dark blue mottled varieties are prized.
| Kind | lithic |
|---|---|
| Regions | North America — Eastern Woodlands |
Sources
The Upper Mercer limestone of the Pennsylvanian Pottsville group crops out in Coshocton, Muskingum, Tuscarawas and Holmes counties, Ohio, with quarries at Warsaw and along the Walhonding River. Cobbles occur in glacial outwash south into the Ohio Valley.
Identification
The chert is black, dark grey or blue-grey, sometimes mottled with lighter grey or with white 'Nellie' inclusions, opaque with a dull to slightly glossy lustre. Weathering produces a lighter grey or bluish patina. Fossils are uncommon.
Substitutes and fakes
Modern Turkey-tail and Adena reproductions in Upper Mercer are known; freshly worked surfaces are uniformly black and lack the bluish patina of genuine pieces. Provenance matters.
Cite this article
Stratum Strata. "Upper Mercer chert" (Material). Stratum Strata pack 2026.09, as of 2026-09-21. https://stratum.black/strata/materials/upper-mercer-chert. Accessed 2026-09-21.
@misc{stratum-upper-mercer-chert,
title = {Upper Mercer chert},
author = {{Stratum Strata}},
howpublished = {\url{https://stratum.black/strata/materials/upper-mercer-chert}},
year = {2026},
note = {Material article, Stratum Strata pack 2026.09, as of 2026-09-21; sources: stratum, commons. Accessed 2026-09-21.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.