sedimentary

Moqui Marble

Hematite-Goethite Concretion

Hardness: 5.5 to 6.5 on the Mohs scale. Color: Brownish-black exterior with a light brown, sandy interior. Luster: Metallic to dull. Crystal structure: Amorphous to microcrystalline concretionary mass. Specific gravity: Approx 3.8 - 4.5.

Hardness: 5
Color: Brownish-black exterior with a light brown, sandy interior
Luster: Metallic to dull

Identified August 6, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in sedimentary sandstone environments, specifically within the Navajo Sandstone of Utah. They are concretions created by iron-rich groundwater precipitating iron oxides around a nucleation center.

Uses & applications

Popular among mineral collectors, used in metaphysical practices for meditation and grounding, and appreciated as unique natural geological formations.

Geological facts

Also known as shaman stones or Utah berries, Moqui marbles are often found eroding out of ancient Jurassic-aged sandstone formations. Similar ironstone concretions are also found on Mars, discovered by the Opportunity rover.

Field identification & locations

Found weathering out of sandstone cliffs in the American Southwest, particularly Utah. Easily identified by their spherical or disk-like shape with a hard iron shell encasing softer sandstone.