metamorphic
Gneiss
Gneiss
AI-generated identification · may be incorrectHardness of 6-7 on Mohs scale, banded or foliated texture, typically composed of alternating lighter quartz/feldspar layers and darker biotite/amphibole layers.
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Physical properties
Hardness of 6-7 on Mohs scale, banded or foliated texture, typically composed of alternating lighter quartz/feldspar layers and darker biotite/amphibole layers.
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 the construction industry as crushed stone for road bases, building facades, and dimension stone.
Geological facts
Gneiss contains some of the oldest known rocks on Earth, with certain samples dating back over 4 billion years.
Field identification & locations
Easily identified by its distinctive alternating light and dark mineral bands, commonly found in ancient shield areas of continental crust.
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