igneous
Likely rhyolite or altered volcanic rock
Fine-grained felsic volcanic rock, probably rhyolite; exact identification is uncertain from the image
AI-generated identification · may be incorrectSmall, rough, mottled gray and reddish specimen with a fine-grained appearance; hardness and luster cannot be determined reliably from the photo. Rhyolite is quartz- and feldspar-rich, commonly with Mohs hardness around 6–7.
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Physical properties
Small, rough, mottled gray and reddish specimen with a fine-grained appearance; hardness and luster cannot be determined reliably from the photo. Rhyolite is quartz- and feldspar-rich, commonly with Mohs hardness around 6–7.
Formation & geological history
If rhyolite, it formed when silica-rich lava cooled rapidly at or near the surface. Such rocks occur in volcanic terrains of many ages; the specimen’s age and provenance are unknown.
Uses & applications
Rhyolite is used as crushed aggregate and, when attractive or workable, as a decorative or collecting stone.
Geological facts
Red coloration can result from iron oxides, but similar colors and textures occur in several volcanic rocks and altered materials.
Field identification & locations
The specimen appears geological, but the photo is insufficient for a firm identification. Examine a fresh surface, grain size, and hardness; common rhyolite localities include volcanic regions worldwide.
