igneous
Rhyolite pebble (likely flow-banded rhyolite)
Rhyolite; fine-grained, silica-rich volcanic rock, typically quartz and alkali feldspar
AI-generated identification · may be incorrectRounded, pale cream and dusty pink-red surface with irregular darker bands and fractures; likely aphanitic, with hardness around 6–7 Mohs and a dull to slightly silky luster. The image does not show crystals clearly enough to confirm the exact mineral mix or banding.
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Physical properties
Rounded, pale cream and dusty pink-red surface with irregular darker bands and fractures; likely aphanitic, with hardness around 6–7 Mohs and a dull to slightly silky luster. The image does not show crystals clearly enough to confirm the exact mineral mix or banding.
Formation & geological history
Rhyolite forms when silica-rich lava cools rapidly at or near the surface; flow textures develop as lava moves. Its age and original geological setting cannot be determined from the photograph.
Uses & applications
Commonly collected as a decorative pebble or lapidary material; rhyolite is also used locally as crushed stone or building stone.
Geological facts
Rhyolite is the volcanic equivalent of granite, but its crystals are usually much finer because it cools faster.
Field identification & locations
Look for fine grain, pale pink or cream coloration, and possible flow bands; a fresh broken surface is more diagnostic than this weathered, rounded pebble. Rhyolite occurs in volcanic regions worldwide.
