Shale formation with numerous horizontal beds of rock at Marble Canyon in Kootenay National Park, in the Canadian province of British Columbia (2025)

>Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals and silt-sized particles of other minerals, especially quartz and calcite. It is characterized by fissility, the tendency to split into thin layers less than 1 centimetre (0.39 in) in thickness, and is the most common sedimentary rock.

Photographer: [Chris Woodrich](https://en.wikipedia.org/wiki/User:Crisco_1492)

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