artifact / sedimentary or igneous rock

Native American Hammerstone / Pitted Stone

Modified lithic artifact (often quartzite, basalt, or granite)

Hardness: varies based on base rock (typically 6-7 on Mohs scale for quartzite/granite); Color: gray, brown, or weathered earth tones; Luster: dull to earthy; Structure: massive, artificially shaped by pecking and grinding with an ergonomic thumb/finger depression (nutting stone or hammerstone)

Color: gray, brown, or weathered earth tones
Luster: dull to earthy

Identified August 3, 2026More artifact / sedimentary or igneous rock →

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Physical properties

Formation & geological history

Formed through natural geological processes (sedimentary deposition or igneous cooling), subsequently shaped and utilized by indigenous peoples globally as a prehistoric tool for hammering, grinding, or cracking nuts, dating from various archaeological periods (Paleolithic to Woodland/Mississippian periods)

Uses & applications

Historical and archaeological value; used in antiquity as a percussion tool, hammerstone, or anvil stone for flintknapping, food processing, and craft-making

Geological facts

Pitted stones, sometimes called nutting stones, feature one or more manufactured indentations. Their exact historical function is debated among archaeologists, ranging from nut cracking to fire-starting (hearth drills) or pigment grinding

Field identification & locations

Identified by symmetrical or intentional shaping, smoothed surfaces from handling, and distinct pecked depressions that do not occur via natural weathering; often found near historical waterways, ancient camp sites, or plowed agricultural fields

Other artifact / sedimentary or igneous rock specimens

See all

Nutting Stone / Cupstone (Sandstone or Quartzite)

Sedimentary rock with anthropogenic modification (cupule)

sedimentary

Quartz Heart or Arrowhead Shape

Silicon Dioxide (SiO2)

mineral

Pitted Sedimentary Rock / Cupstone

Sedimentary rock with weathering pit (arenite / sandstone)

sedimentary

Granodiorite

Phaneritic Plutonic Intermediate-Felsic Rock

igneous

Not a geological specimen

N/A (man-made object)

N/A

Chert Arrowhead (Lithic Artifact)

Chert (Cryptocrystalline Quartz, SiO2)

sedimentary