sedimentary
Iron Concretion
Limonite or Hematite Concretion
AI-generated identification · may be incorrectHardness of 4.5 to 5.5, dark brown to reddish-black color, earthy to submetallic luster, amorphous or microcrystalline structure.
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Physical properties
Hardness of 4.5 to 5.5, dark brown to reddish-black color, earthy to submetallic luster, amorphous or microcrystalline structure.
Formation & geological history
Formed in sedimentary rocks through the precipitation of iron minerals from groundwater moving through permeable strata.
Uses & applications
Collected as geological curiosities and sometimes used for lapidary display or historical iron ore extraction.
Geological facts
Often mistaken for meteorites due to their heavy weight and dark, rounded exterior crust.
Field identification & locations
Identify by its unusually high density, irregular spherical shape, and reddish streak on unglazed porcelain. Commonly found in sedimentary clay and sandstone deposits.
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Sandstone or Siltstone
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