igneous
Rhyolite
Extrusive igneous rock (felsic)
Hardness: 6 on Mohs scale. Color: Light gray, off-white, tan, or pink. Luster: Dull to vitreous. Crystal structure: Aphanitic (fine-grained) to glassy, often with phenocrysts.
- Hardness
- 6 on Mohs scale
- Color
- Light gray, off-white, tan, or pink
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6 on Mohs scale. Color: Light gray, off-white, tan, or pink. Luster: Dull to vitreous. Crystal structure: Aphanitic (fine-grained) to glassy, often with phenocrysts.
Formation & geological history
Formed from the rapid cooling of silica-rich lava on or near the Earth's surface, typically in volcanic settings associated with continental calderas.
Uses & applications
Used locally in construction aggregate, road metal, and sometimes as a decorative stone.
Geological facts
Rhyolite is the extrusive equivalent of granite, meaning they share the same mineral composition (quartz, feldspar) but cooled differently.
Field identification & locations
Found worldwide in volcanic regions; identified by its light color, fine-grained texture, and sometimes porphyritic texture with visible quartz or feldspar crystals.
