mudstone

American  

[muhd-stohn] / ˈmʌdˌstoʊn /

noun

Geology.

1. a clayey rock with the texture and composition of shale but little or no lamination.

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mudstone British  

/ ˈmʌdˌstəʊn /

noun

1. a dark grey clay rock similar to shale but with the lamination less well developed

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mudstone Scientific  

/ mŭd′stōn′ /

1. A fine-grained, dark gray sedimentary rock consisting primarily of compacted and hardened silt and clay, similar to shale but without laminations. The proportions of silt and clay in mudstone are approximately equal.

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Etymology

Origin of mudstone

First recorded in 1730–40; mud + stone

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Compare meaning

How does mudstone compare to similar and commonly confused words? Explore the most common comparisons:

• mudstone vs. shale

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Example Sentences

See Examples For:

mudstone

Some of these cores at the Northern Territory Geological Survey are mudstone – a type of sedimentary rock formed from hardened seafloor mud.

From Science Daily ● Sep. 27, 2026

The excavation process took longer than usual, about 10 days, since the fossils were encased in very hard mudstone under six feet of rock, he said.

From Los Angeles Times ● Sep. 24, 2026

Spotted in July 2024, the reddish mudstone contains organic compounds and other minerals that could have supported bygone microbial Martians.

From The Wall Street Journal ● Apr. 23, 2026

They are about 3.5bn years old and are a type of rock called mudstone, which is fine-grained rock formed from clays.

From BBC ● Sep. 10, 2025

The uppermost, dark-coloured, hard mudstone, bed 12, is in this neighbourhood the most constant stratum.

From Geological Observations on South America by Charles Darwin

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