metamorphic

Likely slate fragment

Slate; fine-grained foliated metamorphic rock, commonly quartz–mica–chlorite rich

AI-generated identification · may be incorrect

Dark gray-green, dull to weakly silky luster, very fine grained, with planar cleavage and thin platy edges. Typical hardness is about 3–5 Mohs; no visible crystals or strong crystal faces are apparent.

Identified August 12, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when shale or mudstone undergoes low-grade regional metamorphism, usually during mountain building; individual pieces may be Paleozoic to younger depending on source region.

Uses & applications

Used for roofing, flooring, paving, wall cladding, chalkboards, and decorative objects; this small irregular fragment has negligible commercial value.

Geological facts

Slate splits along slaty cleavage, unlike many massive dark rocks. The greenish color may reflect chlorite or other low-grade metamorphic minerals.

Field identification & locations

Common in metamorphic belts worldwide, including Wales, Spain, Vermont, Portugal, and Appalachia. Confirm by testing whether it splits into smooth thin sheets; a dark coating or wet surface can obscure its texture.