sedimentary
Sandstone Concretion
Sedimentary Concretion (Quartz sand bound by mineral cement)
Hardness varies from 6 to 7 depending on cement; Color ranges from tan, brown, to grey; Luster is dull to earthy; Structure is typically rounded or spherical mass.
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Physical properties
Hardness varies from 6 to 7 depending on cement; Color ranges from tan, brown, to grey; Luster is dull to earthy; Structure is typically rounded or spherical mass.
Formation & geological history
Formed by the precipitation of mineral cement within the pores of sedimentary rocks, often around a nucleus, typically during burial diagenesis.
Uses & applications
Collectible geological specimen, educational tool, and lapidary curiosity.
Geological facts
Concretions are often mistaken for fossils or manufactured objects due to their spherical or unusual shapes.
Field identification & locations
Found worldwide in sedimentary formations, particularly in sandstone layers; identified by their distinct rounded form contrasting with surrounding host rock.
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