igneous
Weathered volcanic rock (likely vesicular basalt)
Basalt, a fine-grained mafic volcanic rock; exact identification is uncertain from the image
AI-generated identification · may be incorrectGray, rough, and fine-grained, with possible small cavities and pale mineral grains. Basalt typically contains plagioclase and pyroxene, sometimes olivine; hardness is about 6, luster dull, and crystals too small to see unaided.
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Physical properties
Gray, rough, and fine-grained, with possible small cavities and pale mineral grains. Basalt typically contains plagioclase and pyroxene, sometimes olivine; hardness is about 6, luster dull, and crystals too small to see unaided.
Formation & geological history
Forms when iron- and magnesium-rich lava cools at or near Earth’s surface; specimens may range from recent to billions of years old. The visible roughness may reflect weathering or gas bubbles, but cannot be confirmed from the image.
Uses & applications
Crushed basalt is used as aggregate, road stone, and construction material; this small specimen is mainly suitable for study or collecting.
Geological facts
Basalt is among Earth’s most abundant volcanic rocks and forms much of the ocean floor.
Field identification & locations
Look for a dark, dense groundmass and fine grains; vesicles may indicate trapped gas. A fresh broken surface and a closer view would help distinguish basalt from other weathered volcanic rocks.
