igneous
Vesicular volcanic rock, likely pumice or scoriaceous rhyolite
Highly vesicular felsic volcanic rock; commonly rhyolitic pumice (composition dominated by volcanic glass, quartz, and alkali feldspar)
AI-generated identification · may be incorrectPale pink-gray, porous, and weathered, with abundant rounded gas cavities (vesicles), dull to slightly vitreous luster, and no obvious cleavage. Likely Mohs hardness about 5–6; density is reduced by vesicles but the specimen appears too dense to float.
Identified More igneous →
Explore Vesicular volcanic rock, likely pumice or scoriaceous rhyolite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Pale pink-gray, porous, and weathered, with abundant rounded gas cavities (vesicles), dull to slightly vitreous luster, and no obvious cleavage. Likely Mohs hardness about 5–6; density is reduced by vesicles but the specimen appears too dense to float.
Formation & geological history
Formed when gas-rich silica magma erupted explosively and rapidly quenched, trapping bubbles in volcanic glass; likely Cenozoic or younger, though the exact age cannot be determined from the image.
Uses & applications
Pumice is used as a lightweight abrasive, exfoliant, horticultural additive, and concrete aggregate; decorative volcanic specimens are inexpensive collectibles.
Geological facts
The pink coloration may reflect iron oxidation or weathering, while dark green-black patches could be mafic minerals or secondary alteration. Its texture distinguishes it from ordinary granite and most sedimentary rocks.
Field identification & locations
Identify by very high vesicularity, glassy texture, and irregular cavities; pumice is usually lightweight and may float, whereas scoria is darker and basaltic. Common around explosive volcanic fields worldwide.
