igneous
Vesicular basalt (scoriaceous basalt)
Basalt; chiefly plagioclase feldspar, pyroxene, and often olivine
AI-generated identification · may be incorrectDark gray, highly vesicular, dull to weakly earthy luster; typically fine-grained with hardness about 6 on Mohs scale, no prominent cleavage, and specific gravity roughly 2.6–3.0. The cavities are gas bubbles, commonly lined with alteration minerals.
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Physical properties
Dark gray, highly vesicular, dull to weakly earthy luster; typically fine-grained with hardness about 6 on Mohs scale, no prominent cleavage, and specific gravity roughly 2.6–3.0. The cavities are gas bubbles, commonly lined with alteration minerals.
Formation & geological history
An extrusive volcanic rock formed when mafic lava cooled rapidly at or near the surface, trapping abundant gas bubbles; age depends on locality and may range from recent lava flows to ancient volcanic terrains.
Uses & applications
Used as lightweight aggregate, landscaping stone, road material, and occasionally as a decorative or lapidary specimen; generally low jewelry value.
Geological facts
Its abundant holes distinguish scoria or vesicular basalt from dense basalt; rusty patches may reflect oxidation of iron-bearing minerals.
Field identification & locations
Common in volcanic regions such as Hawaii, Iceland, Japan, the Andes, and western North America. Identify it by its dark mafic color, rough texture, vesicles, and relatively heavy feel compared with pumice; a magnet may show weak attraction.
