Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
claystone
Introduction References & Edit History Related Topics
Quick Facts
Related Topics:
clay
mudrock
clastic rock
See all related content
Britannica AI Icon
Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites

claystone

geology
Written and fact-checked by
Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
Britannica Editors
History

claystone, hardened clay. Some geologists further restrict the term to a sedimentary rock that is composed primarily of clay-sized particles (less than 1/256 millimetre in diameter) and is not laminated or easily split into thin layers; such rocks that show cleavage roughly parallel to the bedding plane often are classed as clay shales. Claystones that are massive and blocky are sometimes called mudstones, but some geologists class as mudstones partly hardened muds that slake when wetted, reserving the term claystone for fully hardened material.