igneous
Light-colored volcanic rock fragment, likely pumice or tuff
Pumice (vesicular volcanic glass) or volcanic tuff; not identifiable more precisely from the image
AI-generated identification · may be incorrectPale gray, rough and apparently porous, with a dull to slightly glassy surface. Pumice is typically Mohs 5–6 with a glassy, noncrystalline texture; tuff hardness and composition vary.
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Physical properties
Pale gray, rough and apparently porous, with a dull to slightly glassy surface. Pumice is typically Mohs 5–6 with a glassy, noncrystalline texture; tuff hardness and composition vary.
Formation & geological history
Forms from silica-rich volcanic ash and gas-rich lava during explosive eruptions; pumice may be geologically young, while tuff ranges widely in age. The photo does not show enough detail to confirm vesicles or distinguish the two.
Uses & applications
Pumice is used as an abrasive, lightweight aggregate, and horticultural material; tuff is used as building stone and aggregate. This small fragment has little commercial value.
Geological facts
Pumice can be so vesicular that it floats; tuff is consolidated volcanic ash.
Field identification & locations
Look for abundant pores and very low weight for pumice, or compacted ash and visible angular fragments for tuff. Similar volcanic rocks occur near volcanic regions worldwide; a hand sample or magnified view would help distinguish them.
