sedimentary
Moqui Marbles
Ironstone Concretions (Hematite / Goethite / Sandstone)
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
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Physical properties
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
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.
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