igneous
Vesicular basalt with secondary mineralization
Mafic volcanic rock, chiefly plagioclase and pyroxene, with iron oxides and likely zeolite/calcite infillings
AI-generated identification · may be incorrectDark gray-green, fine-grained, dull to slightly glassy, with abundant vesicles and rusty red-brown weathering; hardness about 5–6, typically massive with no obvious cleavage. The cavities may contain pale zeolitic or carbonate minerals, though the photo cannot confirm them.
Identified More igneous →
Explore Vesicular basalt with secondary mineralization in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray-green, fine-grained, dull to slightly glassy, with abundant vesicles and rusty red-brown weathering; hardness about 5–6, typically massive with no obvious cleavage. The cavities may contain pale zeolitic or carbonate minerals, though the photo cannot confirm them.
Formation & geological history
Formed when basaltic lava cooled rapidly at or near the surface, trapping gas bubbles; later groundwater oxidized iron and deposited secondary minerals. Its precise geological age and locality cannot be determined visually.
Uses & applications
Used as aggregate, road stone, riprap, and landscaping material; attractive zeolite-lined or mineral-filled pieces are collected, but ordinary specimens have little commercial value.
Geological facts
Vesicles distinguish it from most intrusive igneous rocks; red coloration commonly reflects hematite or other iron-oxide weathering. The texture is consistent with volcanic basalt rather than a metamorphic or sedimentary rock.
Field identification & locations
Identify by its dark fine-grained matrix, low apparent quartz content, vesicles, and relatively high density; a streak, acid test, hardness test, and close inspection of cavity minerals would refine identification. Common in volcanic terrains and basalt lava flows worldwide.
