sedimentary
Clay Concretion / Mudstone Nodule
Sedimentary Concretion (Argillaceous)
AI-generated identification · may be incorrectMohs hardness 2-4, dull to earthy luster, rounded to irregular nodular shape, and tan, greyish, or buff-brown coloration.
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Physical properties
Mohs hardness 2-4, dull to earthy luster, rounded to irregular nodular shape, and tan, greyish, or buff-brown coloration.
Formation & geological history
Formed via diagenesis through precipitation of mineral cement in sedimentary mud or clay layers over geological time.
Uses & applications
Primarily of geological curiosity; occasionally utilized in ceramic testing or general gravel fill.
Geological facts
Concretions often form concentrically around an organic nucleus, such as a fossil shell or plant matter.
Field identification & locations
Identifiable by its smooth to irregular rounded exterior and fine-grained, earthy texture in stream beds or clay strata.
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