metamorphic
Weathered foliated metamorphic rock, likely schist or gneiss
Micaceous quartz–feldspar metamorphic rock; exact mineralogy requires testing
AI-generated identification · may be incorrectGray-brown, fine- to medium-grained, weakly layered/foliated, dull earthy luster with dark mineral streaks and fractures. Typical hardness is about 5–7 Mohs; cleavage is poor overall but mica may split along foliation.
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
Gray-brown, fine- to medium-grained, weakly layered/foliated, dull earthy luster with dark mineral streaks and fractures. Typical hardness is about 5–7 Mohs; cleavage is poor overall but mica may split along foliation.
Formation & geological history
Formed when shale or other sedimentary rock was buried, heated, and compressed during regional metamorphism, commonly hundreds of millions to billions of years ago. Surface weathering has rounded and stained the specimen.
Uses & applications
Used locally as building stone, wall rock, landscaping stone, and aggregate; attractive foliated pieces may be collected or polished, but this example appears mainly of modest specimen value.
Geological facts
The visible planar fabric reflects alignment of pressure-sensitive minerals such as mica, chlorite, or amphibole. A magnet, streak test, acid test, and fresh break would help distinguish schist from gneiss and identify iron-bearing minerals.
Field identification & locations
Common in continental mountain belts and exposed Precambrian terrains worldwide, including parts of the Appalachians, Canadian Shield, Scandinavia, and India. Look for foliation, mica sparkle, quartz-rich bands, and resistance to dilute acid.
More like this
