metamorphic
Gneiss
Metamorphic silicate rock
AI-generated identification · may be incorrectHardness 6-7 on Mohs scale, banded or foliated texture with alternating light and dark layers, vitreous to dull luster, specific gravity 2.6-2.9.
Identified More metamorphic →
Explore Gneiss in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 6-7 on Mohs scale, banded or foliated texture with alternating light and dark layers, vitreous to dull luster, specific gravity 2.6-2.9.
Formation & geological history
Formed through high-temperature and high-pressure regional metamorphism of pre-existing igneous or sedimentary rocks deep within the Earth's crust.
Uses & applications
Used primarily in construction, as crushed stone for road bases, and occasionally as dimension stone for building facades.
Geological facts
Gneiss contains some of the oldest known geological materials on Earth, with certain zircon grains dating back over 4 billion years.
Field identification & locations
Identify by its distinct alternating light and dark mineral bands (gneissic banding). Commonly found in ancient cratons and shield areas worldwide.
More like this
