sedimentary

Moqui Marbles

Ironstone Concretions (Hematite / Goethite / Sandstone)

AI-generated identification · may be incorrect

Hardness: 5.5 - 6.5 (outer shell); Color: Dark reddish-brown, chocolate brown, blackish-brown; Luster: Metallic to earthy; Structure: Spherical to rounded botryoidal sandstone core encased in a limonite/hematite shell; Specific Gravity: 3.0 - 4.0

Hardness: 5
Color: Dark reddish-brown, chocolate brown, blackish-brown
Luster: Metallic to earthy

Identified July 22, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in the Navajo Sandstone formation in southern Utah during the Jurassic to Cenozoic eras. Dissolved iron in groundwater precipitated around sand grains, creating rounded iron-oxide concretions exposed by erosion.

Uses & applications

Popular as geological display specimens, educational items, and metaphysical/healing stones ('shaman stones').

Geological facts

Also known as Moki Balls or Shaman Stones. They are named after the Hopi Native Americans (formerly referred to as Moqui). NASA found similar iron-oxide concretions on Mars, nicknamed 'blueberries,' which provided evidence of ancient liquid water.

Field identification & locations

Identified by their distinct round, peanut-like, or spherical shape with a hard, dark iron-oxide crust and fine-grained sandstone interior. Found mainly in the Navajo Sandstone of southern Utah, USA. Note: Collecting them inside Grand Staircase-Escalante National Monument is federally protected and prohibited.