igneous
Weathered vesicular volcanic rock (likely pumice/tuff)
Porous volcanic pyroclastic rock, probably pumiceous tuff; exact identification requires testing
AI-generated identification · may be incorrectLight tan-gray, highly porous and crumbly with rusty iron-oxide staining and possible green secondary minerals; likely hardness ~4–6, dull to weakly earthy luster, no visible cleavage, low density. The cavities indicate abundant vesicles or pyroclastic pores.
Identified More igneous →
Explore Weathered vesicular volcanic rock (likely pumice/tuff) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Light tan-gray, highly porous and crumbly with rusty iron-oxide staining and possible green secondary minerals; likely hardness ~4–6, dull to weakly earthy luster, no visible cleavage, low density. The cavities indicate abundant vesicles or pyroclastic pores.
Formation & geological history
Formed from gas-rich volcanic magma that explosively erupted and solidified as frothy fragments or ash; its age cannot be determined from the photograph. Surface weathering produced the brown staining and altered minerals.
Uses & applications
Used as lightweight aggregate, abrasives, horticultural soil amendment, and decorative stone; this specimen has little commercial value unless tied to a notable volcanic locality.
Geological facts
Pumice commonly floats when freshly collected, while tuff is a compacted ash rock and usually sinks. Green coloration may reflect chlorite, epidote, or other weathering products.
Field identification & locations
Look for very low density, abundant irregular pores, sharp vesicle walls, and a gritty volcanic texture; distinguish it from slag or concrete by natural, nonuniform fabric. Common near young volcanic fields worldwide.
