metamorphic
Likely slate fragment
Slate; fine-grained foliated metamorphic rock, commonly quartz–mica–chlorite rich
AI-generated identification · may be incorrectDark 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 More metamorphic →
Explore Likely slate fragment in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
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.
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.
More like this
