sedimentary
Fine-grained sedimentary rock, likely mudstone
Mudstone (clay- and silt-sized siliciclastic sedimentary rock)
AI-generated identification · may be incorrectDull, tan-brown, fine-grained and rounded, with subtle layering; likely hardness around 2–4 Mohs. Mineral composition is probably clay minerals and fine quartz, but cannot be confirmed from the image.
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Physical properties
Dull, tan-brown, fine-grained and rounded, with subtle layering; likely hardness around 2–4 Mohs. Mineral composition is probably clay minerals and fine quartz, but cannot be confirmed from the image.
Formation & geological history
Forms when clay and silt settle in quiet water and become compacted and cemented; its age and exact depositional setting cannot be determined visually.
Uses & applications
Commonly used as a geological specimen; mudstone may also be quarried as aggregate or feedstock for bricks and cement.
Geological facts
Mudstone is similar to shale but typically lacks shale’s strong tendency to split into thin sheets.
Field identification & locations
A fine, earthy texture and faint layers support identification; the specimen’s rounded shape may result from transport or weathering. Mudstone occurs in sedimentary basins worldwide.
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