sedimentary

Moqui Marble

Ironstone Concretion (Goethite/Hematite shell with Sandstone core)

AI-generated identification · may be incorrect

Hardness: 5-5.5 (shell), 2-3 (core); Color: dark brown to black exterior, tan interior; Luster: earthy to sub-metallic; Structure: concretionary/spherical; Specific Gravity: 3.2-4.1

Hardness: 5-5
Color: dark brown to black exterior, tan interior
Luster: earthy to sub-metallic

Identified April 23, 2026More sedimentary →

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Physical properties

Hardness: 5-5.5 (shell), 2-3 (core); Color: dark brown to black exterior, tan interior; Luster: earthy to sub-metallic; Structure: concretionary/spherical; Specific Gravity: 3.2-4.1

Formation & geological history

Formed roughly 130 to 180 million years ago within the Navajo Sandstone. Created by the precipitation of iron-rich minerals from groundwater around a nucleus, often during the oxidation of siderite.

Uses & applications

Predominantly used as collectible mineral specimens, educational tools, and in metaphysical practices (shaman stones). Primarily found on the Colorado Plateau.

Geological facts

Also known as Moqui Balls or Shaman Stones, these are named after the Moqui (Hopi) people. They are naturally occurring spheres that look like rusty cannonballs or marbles.

Field identification & locations

Identify by their distinct spherical or disk-like shape and sandy interior when broken. Commonly found in Utah and Arizona. They are protected by law in US National Parks.