Knox Group chert

Also called Knox chert, Red Knox, Black/Gray Knox, Knox Black chert, Ridge and Valley chert

Knox Group chertChert (and flint)Southeast

Description

Knox chert is the chert of the Knox Group dolomite, which underlies the long valleys of eastern Tennessee, northwestern Georgia and the Coosa Valley of Alabama. In the Georgia valleys, weathering of the dolomite scatters gray chert boulders and chunks across the landscape. The stone varies widely from outcrop to outcrop. Tennessee archaeologists describe fine-grained, translucent black or blue varieties, while Alabama collections include a red Knox with quartz bands and a black-to-gray Knox with translucent gray mottling. It flakes fair to good unless quartz inclusions or flaws spoil the fracture, and the variability makes it hard to identify.

How to identify it

Colour: Gray in the Georgia valleys (Wood and Bowen); black or blue and translucent in Tennessee (Parish and Durham); 'Red Knox' resembles good heated Tuscaloosa gravel; 'Black/Gray Knox' is dark gray to black with translucent gray mottling, and a non-translucent mottled form also exists (Barry).
Texture: Fine grained in Tennessee; Red Knox is finer than Tuscaloosa gravel.
Luster: Higher luster in Red Knox than Tuscaloosa gravel; the Ashe Ferry specimens are described as highly lustrous.
Inclusions: Quartz inclusions, sometimes as a band, in Red Knox (Barry).

Geology

The Ordovician Knox Group (dolomite) crops out in the Ridge and Valley province. Between Cartersville and Rome in northwest Georgia, the Knox dolomite underlies about half of the Rome Valley and yields large quantities of gray chert on weathering; exposures of the dolomite itself are rare. In Alabama the Knox formation of the eastern Coosa Valley supplied the Knox chert in Barry's study; the likely collecting source for that stone was the Tallapoosa River (Barry, citing a local flintknapper).

Where it comes from

Southeast

States

Quarries and outcrops

Ridge and Valley of eastern Tennessee (Knox Black chert)
Rome Valley, Cartersville to Rome, northwest Georgia
Eastern Coosa Valley, Alabama

Used by

Late prehistoric: Knox Black-type chert occurs in low to moderate amounts in assemblages of western North Carolina (Ashe Ferry report, citing Dickens 1976 and Kimball 1985)
Found at (not a source): Western North Carolina assemblages contain Knox Black-type chert as a non-local stone (Ashe Ferry report)

Look-alikes

Stones that are easy to confuse with Knox Group chert.

Black Bangor chert, which has similar colour but is translucent (Barry)
Tuscaloosa gravel chert, resembled by Red Knox
Other Ridge and Valley chert (Georgia valleys)

Sources

Wood, W. Dean, and William R. Bowen. 1995. Woodland Period Archaeology of Northern Georgia. University of Georgia Laboratory of Archaeology Series Report 33.archaeology.uga.edu (opens in a new tab)
Barry, Steven Edward. 2004. Lithic Raw Materials and Chipped Stone Tools: A Comparison of Two Sites in the Moundville Chiefdom. M.A. thesis, Department of Anthropology, University of Alabama, Tuscaloosa.rla.unc.edu (opens in a new tab)
Parish, Ryan M., and Ellis Durham. 2018. KRF look-a-likes in Tennessee. 30 Days of Tennessee Archaeology, Day 22. Tennessee Council for Professional Archaeology (blog).tennesseearchaeologycouncil.wordpress.com (opens in a new tab)
Research Laboratories of Archaeology, University of North Carolina at Chapel Hill. Research Report 36, Chapter 6: Chipped-Stone, Ground-Stone, and Other Artifacts (Ashe Ferry site, Carolina Piedmont; PDF dated 2015).rla.unc.edu (opens in a new tab)
Research Laboratories of Archaeology, UNC Chapel Hill. Research Report 36, Chapter 6 (Ashe Ferry site).rla.unc.edu (opens in a new tab)

All materials