metamorphic
Gneiss
Gneiss
AI-generated identification · may be incorrectHardness of 6-7 on the Mohs scale, characterized by distinct alternating light and dark mineral bands (foliation). It has a vitreous to dull luster and a crystalline structure.
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Physical properties
Hardness of 6-7 on the Mohs scale, characterized by distinct alternating light and dark mineral bands (foliation). It has a vitreous to dull luster and a crystalline structure.
Formation & geological history
Formed through high-grade regional metamorphism of pre-existing igneous or sedimentary rocks under intense heat and directional pressure.
Uses & applications
Widely used as crushed stone for road construction, building facades, landscaping, and monumental stone.
Geological facts
Some gneiss formations contain some of the oldest rocks on Earth, dating back over 4 billion years.
Field identification & locations
Easily identified in the field by its striking zebra-like banding known as gneissic banding. Found globally in ancient continental shields.
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