sedimentary

Moqui Marble (Shaman Stone)

Ironstone Concretion (Goethite/Hematite over Sandstone)

Hardness: 5.0 to 5.5 on Mohs scale; Color: Dark brown to black exterior, tan/yellow interior; Luster: Dull to sub-metallic; Crystal structure: Amorphous to microcrystalline; Cleavage: None; Specific gravity: approx. 3.4-4.2

Hardness: 5
Color: Dark brown to black exterior, tan/yellow interior
Luster: Dull to sub-metallic

Identified July 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in the Navajo Sandstone of Utah during the Jurassic period. They are created by the precipitation of iron oxides (hematite and goethite) from groundwater circulating through porous sandstone, often forming around a nucleus.

Uses & applications

Mainly used as collectible geological specimens, in metaphysical practices (shaman stones), and occasionally for educational purposes.

Geological facts

These concretions can range from the size of a pea to a baseball. Legend says Hopi ancestors' spirits play with the marbles at night. They are legally protected within Grand Staircase-Escalante National Monument and cannot be collected there.

Field identification & locations

Identified by their round, marble-like shape and heavy dark iron-rich crust. Commonly found weathering out of sandstone cliffs in the American Southwest, particularly Utah.

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Sandstone or Siltstone

Arenite (if sandstone)

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Brown Sandstone (River Rock)

Arenite

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Mudstone

Argillite / Siliciclastic sedimentary rock

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Cone-in-cone structure (Limestone)

Cone-in-cone structure (Secondary Sedimentary Structure)

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Sandstone

Arenite (primarily SiO2)

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Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

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