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Named stone

Kosciusko quartzite

Also called Kosciusko orthoquartzite, Kosciusko Formation quartzite

A kind of quartzite

Kosciusko quartziteQuartziteSoutheast

Description

Kosciusko quartzite is a very hard, fine-grained orthoquartzite from the Eocene Kosciusko Formation of north-central Mississippi, where sand grains are locked together by quartz overgrowths. It is usually gray, sometimes marbled with light red iron staining, and some pieces can only be told from chert under a microscope. Ledges crop out around the town of Kosciusko in Attala County and along the formation's belt from Montgomery to Newton County. It is tough to flake, and the Mississippi point guide notes it had to be quarried and heat-treated. Early knappers mostly avoided it, but Pine Tree point makers used it at the end of the Early Archaic, and Late Woodland and Mississippian arrow-point makers near the outcrops relied on it heavily, for Collins and Madison points above all.

How to identify it

Colour
Typically gray, sometimes with marbled light red iron staining (MDEQ); Madison points of it are generally light mottled gray (McGahey).
Texture
Fine-grained and very hard; quartz overgrowths interlock the sand grains (MDEQ).
Heat treatment
McGahey says it apparently had to be quarried and heat-treated to be workable, and suggests tools of it would have been extremely hard to flake without heating.

Geology

Sedimentary orthoquartzite of the Eocene Kosciusko Formation, typically near the contact with the underlying Zilpha clays (MDEQ). In some cases it can only be distinguished from chert microscopically.

Where it comes from

Southeast

States

Quarries and outcrops

  • Kosciusko, Attala County, Mississippi (outcrops near the town)
  • Kosciusko Formation outcrop belt from Montgomery County to Newton County, Mississippi

Used by

  • End of the Early Archaic: Pine Tree point makers used it for over half their stone (McGahey)
  • Late Woodland to Mississippian: heavy use by arrow-point makers near the outcrops, for Collins and Madison points (McGahey)

Look-alikes

Stones that are easy to confuse with Kosciusko quartzite.

  • Chert: some pieces can only be separated from chert under the microscope (MDEQ)
  • Tallahatta quartzite, the other Mississippi orthoquartzite

Sources

  1. Mississippi Department of Environmental Quality, Office of Geology. Lithic Materials (web page).mdeq.ms.gov (opens in a new tab)
  2. McGahey, Samuel O. 2000 (revised 2004). Mississippi Projectile Point Guide. Archaeological Report No. 31. Mississippi Department of Archives and History, Jackson.mdah.ms.gov (opens in a new tab)

Points made from this stone

All materials