File:Slate_(Knife_Lake_Formation,_metamorphism_at_2.7_Ga,_Neoarchean;_Rt._135_roadcut,_Gilbert,_Minnesota,_USA)_3_(23140002749).jpg · Wikimedia Commons · See Wikimedia Commons
slate
Sign in to saveSlate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression.
Slate is a metamorphic rock formed when clay-rich sedimentary rocks are subjected to heat and pressure deep underground, resulting in a fine-grained stone with natural layering planes. It matters because its unique properties—particularly its ability to split into thin, flat sheets—make it useful for roofing, flooring, and other practical applications.
AI-generated from the Wikipedia summary — may contain errors.
Key facts
- Rock.name
- Slate
- Rock.type
- Metamorphic
- Rock.type_link
- Metamorphic Rock
- Rock.image
- Slate (Knife Lake Formation, metamorphism at 2.7 Ga, Neoarchean; Rt. 135 roadcut, Gilbert, Minnesota, USA) 3 (23140002749).jpg
- Rock.caption
- Slate of the Knife Lake Formation in Minnesota
- Rock.composition
- quartz, muscovite/illite
- Rock.composition_secondary
- biotite, chlorite, hematite, pyrite Specific gravity: 2.7 – 2.8,2.9
via Wikipedia infobox
Wikidata facts
- Image
- St Fagans Tannery 7.jpg
Show 3 more facts
- narrower external class
- purl.org/heritagedata/schemes/eh_tbm/concepts/97716
- Commons category
- Slate
- P8168
- Dover
via Wikidata · CC0
~14 min read
Article
10 sectionsContents
- Description
- Terminology
- Uses
- Construction
- Other uses
- Extraction
- See also
- References
- Further reading
- External links
Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression.
The foliation in slate, called "slaty cleavage", is caused by strong compression in which fine-grained clay forms flakes to regrow in planes perpendicular to the compression. When expertly "cut" by striking parallel to the foliation with a specialized tool in the quarry, many slates display a property called fissility, forming smooth, flat sheets of stone which have long been used for roofing, floor tiles, and billiard tables. Slate is frequently grey in color, especially when seen en masse covering roofs. However, slate occurs in a variety of colors even from a single locality; for example, slate from North Wales can be found in many shades of grey, from pale to dark, and may also be purple, green, or cyan. Slate is not to be confused with shale, from which it may be formed, or schist.