igneous
Weathered, vesicular volcanic rock (likely pumice/scoria)
Pumice or scoriaceous basalt; composition likely volcanic glass with feldspar, pyroxene, and minor iron oxides
AI-generated identification · may be incorrectLight gray to tan, highly vesicular, rough and earthy, with dull to slightly glassy luster; hardness approximately 5–6 for basaltic material, lower where altered. Exact identification is limited because the specimen is dirty and heavily weathered.
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Physical properties
Light gray to tan, highly vesicular, rough and earthy, with dull to slightly glassy luster; hardness approximately 5–6 for basaltic material, lower where altered. Exact identification is limited because the specimen is dirty and heavily weathered.
Formation & geological history
Formed when gas-rich lava rapidly cooled, trapping bubbles; likely Quaternary or younger volcanic material. Common in volcanic fields, lava flows, tephra deposits, and beach or construction fill.
Uses & applications
Pumice is used as an abrasive, lightweight aggregate, horticultural additive, and concrete component; scoria is used for landscaping, drainage, and road aggregate. This fragment has little jewelry or collector value.
Geological facts
The abundant cavities are vesicles created by escaping volcanic gases. Dark patches may be mafic minerals or weathering products, while pale crusts could represent alteration or adhering sediment.
Field identification & locations
Identify by very low density, abundant irregular holes, lack of layering, and a volcanic texture; pumice may float briefly, whereas scoria usually sinks. Common around volcanic regions such as Italy, Iceland, the western United States, and New Zealand.
