metamorphic
Gneiss
Metamorphic Gneiss
AI-generated identification · may be incorrectHardness of 6-7 on the Mohs scale with alternating light and dark compositional banding. It features a vitreous to sub-pearly luster and foliated crystalline structure.
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Physical properties
Hardness of 6-7 on the Mohs scale with alternating light and dark compositional banding. It features a vitreous to sub-pearly luster and foliated crystalline structure.
Formation & geological history
Formed by high-grade regional metamorphism of pre-existing igneous or sedimentary rocks deep within the Earth's crust under extreme heat and pressure.
Uses & applications
Widely used in the construction industry as crushed stone for road bases, building facades, and dimension stone.
Geological facts
Gneiss contains some of the oldest known rock material on Earth, with certain formations dating back over 4 billion years.
Field identification & locations
Easily identified by its distinctive alternating light and dark mineral bands, commonly found in ancient continental shields.
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