metamorphic
Gneiss
Metamorphic Gneiss
AI-generated identification · may be incorrectHardness of 6-7 on Mohs scale, distinct alternating light and dark compositional banding (foliation), vitreous luster, specific gravity of 2.6-2.9.
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Physical properties
Hardness of 6-7 on Mohs scale, distinct alternating light and dark compositional banding (foliation), vitreous luster, specific gravity of 2.6-2.9.
Formation & geological history
Formed through high-grade regional metamorphism of pre-existing igneous or sedimentary rocks under extreme heat and pressure, dating back billions of years.
Uses & applications
Commonly used in construction as crushed stone for road bases, building facades, and dimension stone.
Geological facts
Gneiss includes some of the oldest rocks found on Earth, often exceeding 4 billion years in age. The alternating bands form due to the segregation of minerals like quartz, feldspar, and biotite.
Field identification & locations
Easily identified in the field by its striking zebra-like banding and coarse-grained texture. It is exceptionally common in the Front Range of Colorado near the specified coordinates.
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