sedimentary
Red Claystone / Mudstone
Argillaceous sedimentary rock
Hardness: 2-3 (Mohs scale), Color: Reddish-brown to terracotta, Luster: Dull/Earthy, Crystal structure: Amorphous/Microcrystalline, Cleavage: None (conchoidal or irregular fracture), Texture: Fine-grained and crumbly.
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Physical properties
Hardness: 2-3 (Mohs scale), Color: Reddish-brown to terracotta, Luster: Dull/Earthy, Crystal structure: Amorphous/Microcrystalline, Cleavage: None (conchoidal or irregular fracture), Texture: Fine-grained and crumbly.
Formation & geological history
Formed from the lithification of mud and clay particles. The red color indicates the presence of iron oxides (hematite), suggesting formation in an oxygen-rich environment such as a river floodplain or desert basin.
Uses & applications
Used in the manufacture of bricks, ceramics, and pottery. In pulverized form, it can be used as a pigment (ochre) or as a filler in various industrial products.
Geological facts
Red beds, or sequences of red sedimentary rocks, are often associated with the Permian and Triassic periods and provide evidence of past arid or semi-arid climates on Earth.
Field identification & locations
Identified by its fine grain size, earthy feel, and tendency to break into blocky fragments rather than thin sheets (distinguishing it from shale). It often softens when wet.
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