sedimentary

Weathered gray-green rock fragment

Likely shale or mudstone; exact identification requires testing

AI-generated identification · may be incorrect

Fine-grained, dull to earthy luster, gray-green color, and irregular fracture with possible weak layering. Estimated hardness is about 2–4 Mohs; cleavage and density are not clearly visible.

Identified August 16, 2026More sedimentary →

Explore Weathered gray-green rock fragment in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Fine-grained, dull to earthy luster, gray-green color, and irregular fracture with possible weak layering. Estimated hardness is about 2–4 Mohs; cleavage and density are not clearly visible.

Formation & geological history

Likely compacted and lithified clay- or silt-rich sediment, formed in a quiet-water basin; its geological age cannot be determined from the photograph.

Uses & applications

Common shale and mudstone are used as aggregate, fill, cement raw material, and—if organic-rich—as hydrocarbon source rock. This small specimen has mainly educational or modest collecting value.

Geological facts

The green coloration may reflect chlorite or other iron-bearing clay minerals, while surface roughness suggests weathering. It could also be a weathered fine-grained metamorphic rock such as slate, which would require examining foliation.

Field identification & locations

Look for thin parallel lamination, a powdery clay-like streak, and splitting along bedding; shale is softer and less distinctly foliated than slate. Common occurrences include sedimentary basins worldwide.