igneous
Pumice or Vesicular Basalt/Scoria (water-worn)
Vesicular volcanic rock
Dark gray to black, highly vesicular (full of holes), relatively lightweight depending on composition, dull luster, rough texture but edges smoothed by water erosion.
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Physical properties
Dark gray to black, highly vesicular (full of holes), relatively lightweight depending on composition, dull luster, rough texture but edges smoothed by water erosion.
Formation & geological history
Formed from extrusive volcanic activity where expanding gases get trapped in cooling lava, creating vesicles. The rounded shape indicates it has been tumbled in water, likely on a beach or in a river.
Uses & applications
Used as an abrasive, in lightweight aggregate, landscaping, or as a decorative stone. Pumice is used in cosmetics for exfoliation.
Geological facts
The holes, or vesicles, are frozen gas bubbles that were trapped as the magma rapidly cooled upon reaching the Earth's surface.
Field identification & locations
Easily identified by its pitted surface and relatively low density compared to non-vesicular rocks. Commonly found in volcanic regions or washed up on shores near volcanic islands.
