sedimentary

Nutting Stone / Cupstone (Sandstone or Quartzite)

Sedimentary rock with anthropogenic modification (cupule)

AI-generated identification · may be incorrect

Hardness: 6-7 (if quartzite/silica-cemented sandstone), Color: Orange-brown due to iron oxide (limonite/hematite) staining, Luster: Dull/earthy, Structure: Granular clastic.

Luster: Dull/earthy, Structure: Granular clastic

Identified August 1, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (if quartzite/silica-cemented sandstone), Color: Orange-brown due to iron oxide (limonite/hematite) staining, Luster: Dull/earthy, Structure: Granular clastic.

Formation & geological history

Formed as a sedimentary deposit millions of years ago, later selected and modified by indigenous peoples to create a cupule or anvil stone used for cracking nuts or grinding pigments.

Uses & applications

Archaeological artifact, historical utility for food processing or tool manufacturing, highly valued by artifact collectors.

Geological facts

Stones featuring cup-like depressions are found worldwide and are often associated with ancient ritual practices, nutting, or fire-starting.

Field identification & locations

Identify by the presence of a smooth, deliberately pecked or ground concave depression on a naturally shaped flat rock. Found globally near historical habitation sites.