sedimentary

Moqui Marble (Concretion)

Iron Oxide Concretion

AI-generated identification · may be incorrect

Hardness: 5-6 (outer shell); Color: Brown, tan, rusty red; Luster: Dull/Earthy; Structure: Spherical to subspherical mass; Cleavage: None

Hardness: 5-6 (outer shell)
Color: Brown, tan, rusty red
Luster: Dull/Earthy

Identified July 5, 2026More sedimentary →

Explore Moqui Marble (Concretion) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 5-6 (outer shell); Color: Brown, tan, rusty red; Luster: Dull/Earthy; Structure: Spherical to subspherical mass; Cleavage: None

Formation & geological history

Formed as minerals precipitate from flowing groundwater within porous sedimentary rocks, specifically sandstones like the Navajo Sandstone (Jurassic age).

Uses & applications

Geological research, spiritual or metaphysical collecting, and planetary science analogs (similar to 'blueberries' on Mars).

Geological facts

Also known as Moqui Balls or Shaman Stones, these are often compared to the hematite spherules found by the Opportunity rover on Mars.

Field identification & locations

Commonly found in the American Southwest, specifically Utah and Arizona. They are identified by their distinct spherical shape and dark, hard iron-rich coating.