Ironstone Concretion (Moqui Marble type)

Physical Properties

Hardness: 5.0-6.0; Color: Dark brown to mocha or black exterior; Luster: Dull to earthy/metallic; Crystal structure: Amorphous/massive; Specific gravity: 3.4-4.2.

Formation & Geological History

Formed by the precipitation of iron oxide minerals around a nucleus (often sand) within sedimentary rock layers, typically sandstone. Often associated with Jurassic-aged formations like the Navajo Sandstone.

Uses & Applications

Used primarily as decorative collector pieces, metaphysical 'energy stones', and occasionally crushed for pigment.

Geological Facts

Commonly known as Moqui Marbles or Shaman Stones, these spherical formations are often found in the American Southwest and have been at the center of geological research regarding similar hematite 'blueberries' found on Mars.

Field Identification & Locations

Identify by its spherical to sub-spherical shape, heavy weight for its size (due to iron content), and dark, durable exterior. Often found weathered out of sandstone cliffs in arid environments.

Identified on: 4/13/2026

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