metamorphic

Slate fragment

Slate; predominantly fine-grained mica/clay minerals, commonly muscovite, chlorite, and quartz

AI-generated identification · may be incorrect

Gray-green, very fine-grained, dull to slightly silky luster, with faint planar cleavage/foliation and Mohs hardness about 3–5. The thin, flat shape and layered surface are consistent with slate, though the image alone cannot confirm composition.

Identified September 17, 2026More metamorphic →

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Physical properties

Formation & geological history

Slate forms when shale or mudstone undergoes low-grade regional metamorphism, typically during mountain building. Its age depends on the source formation and may range from Precambrian to recent geologic periods.

Uses & applications

Used for roofing, flooring, paving, blackboards, landscaping, and ornamental items; this small fragment has little commercial value.

Geological facts

Slate splits along closely spaced cleavage planes, unlike most sedimentary mudstone. Greenish coloration commonly reflects chlorite or other low-grade metamorphic minerals.

Field identification & locations

Identify it by its fine texture, planar cleavage, compactness, and ability to split into thin sheets; common sources include metamorphic belts worldwide, especially Wales, Spain, the northeastern United States, and Brazil.