metamorphic
Weathered foliated metamorphic rock, likely schist or gneiss
Mica schist to gneiss; commonly quartz + feldspar + biotite/muscovite
AI-generated identification · may be incorrectMedium- to coarse-grained, gray-brown, with visible foliation and mica-rich layers; vitreous to pearly luster. Typical hardness is about 2–7 depending on mineral, with uneven to foliated fracture and moderate density (2.6–2.8 g/cm³).
Identified More metamorphic →
Explore Weathered foliated metamorphic rock, likely schist or gneiss in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Medium- to coarse-grained, gray-brown, with visible foliation and mica-rich layers; vitreous to pearly luster. Typical hardness is about 2–7 depending on mineral, with uneven to foliated fracture and moderate density (2.6–2.8 g/cm³).
Formation & geological history
Formed when shale or other sedimentary protoliths were buried and subjected to elevated temperature and pressure, recrystallizing minerals and producing foliation. The exact age cannot be determined from the photograph; such rocks range from Precambrian to younger mountain-building events.
Uses & applications
Crushed for aggregate, road base, and fill; sound gneiss can be used as dimension stone, while attractive schist is mainly decorative or collected.
Geological facts
The layered appearance reflects mineral alignment during regional metamorphism rather than original sedimentary bedding. Surface weathering and lichen obscure the exact texture.
Field identification & locations
Look for persistent planar foliation, sparkling mica flakes, quartz veins, and alternating light/dark mineral bands; a hand specimen and fresh break are needed to distinguish schist from gneiss confidently. Common in ancient continental shields and mountain belts.
More like this
