sedimentary
Ironstone Concretion (Boji Stone/Moqui Marble type)
Goethite/Hematite-encrusted Sandstone Concretion
Hardness: 5.0-6.0; Color: Dark brown, rusty orange, or black; Luster: Dull to metallic; Crystal Structure: Amorphous or microcrystalline coating; Specific Gravity: 3.4-5.0.
- Hardness
- 5
- Color
- Dark brown, rusty orange, or black
- Luster
- Dull to metallic
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Physical properties
Hardness: 5.0-6.0; Color: Dark brown, rusty orange, or black; Luster: Dull to metallic; Crystal Structure: Amorphous or microcrystalline coating; Specific Gravity: 3.4-5.0.
Formation & geological history
Formed by the precipitation of iron oxide minerals from groundwater within sedimentary rock layers, often around a nucleus like a leaf, shell, or fossil. They typically range from the Jurassic to the Cenozoic era.
Uses & applications
Primarily used as a collector's specimen, in metaphysical practices (referred to as Shaman stones), and occasionally studied to understand groundwater flow in geological history.
Geological facts
Similar structures have been found on Mars by the Opportunity rover, where they are nicknamed 'blueberries,' suggesting the past presence of water on the red planet.
Field identification & locations
Identify by its spherical or disc shape, heavy weight relative to size (due to iron content), and a rough, pitted, or 'brain-like' surface texture. Commonly found in deserts and badlands.
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