igneous
Rhyolite with K-Feldspar Phenocrysts
Extrusive felsic igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, brownish-gray groundmass with distinct pinkish-red potassium feldspar phenocrysts, dull to vitreous luster, aphanitic texture with visible crystals.
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Physical properties
Hardness of 6 on the Mohs scale, brownish-gray groundmass with distinct pinkish-red potassium feldspar phenocrysts, dull to vitreous luster, aphanitic texture with visible crystals.
Formation & geological history
Formed from rapid cooling of silica-rich lava at or near the Earth's surface, typically during volcanic eruptions in continental settings.
Uses & applications
Used primarily as decorative landscape stone, crushed rock for construction aggregate, and occasionally cut for lapidary purposes.
Geological facts
Rhyolite is the extrusive equivalent of granite, sharing an identical chemical composition but differing significantly in grain size due to cooling rates.
Field identification & locations
Identify in the field by its fine-grained felsic matrix studded with prominent, blocky feldspar crystals. Commonly found in volcanic regions worldwide.
