igneous
Vesicular basalt (weathered volcanic rock)
Basalt, chiefly plagioclase feldspar and clinopyroxene with possible olivine and iron oxides
AI-generated identification · may be incorrectFine-grained, pale gray-beige from weathering, with scattered dark mafic minerals and small vesicles or surface cavities; typically dull to slightly earthy luster, no visible cleavage, hardness about 5–6 Mohs, and specific gravity around 2.7–3.1.
Identified More igneous →
Explore Vesicular basalt (weathered volcanic rock) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Fine-grained, pale gray-beige from weathering, with scattered dark mafic minerals and small vesicles or surface cavities; typically dull to slightly earthy luster, no visible cleavage, hardness about 5–6 Mohs, and specific gravity around 2.7–3.1.
Formation & geological history
Formed when basaltic lava cooled rapidly at or near Earth’s surface, possibly with gas bubbles trapped during eruption; its exact geological age cannot be determined from the photograph. Weathering has lightened the surface and softened textures.
Uses & applications
Common basalt is used as crushed aggregate, roadstone, riprap, and occasionally building stone; attractive specimens are mainly kept for teaching or collecting rather than jewelry.
Geological facts
Basalt is the most abundant volcanic rock on Earth and makes up much of the oceanic crust. The dark inclusions likely represent less-weathered mafic minerals or volcanic fragments.
Field identification & locations
Identify it by its dense fine-grained texture, dark minerals, and vesicles, distinguishing it from porous pumice, which is much lighter. Common worldwide, especially in volcanic regions; a fresh broken surface and streak/acid tests can help confirm it.
