igneous
Scoria (vesicular basalt)
Vesicular basalt, commonly called scoria; chiefly plagioclase, pyroxene, and iron-rich volcanic glass
AI-generated identification · may be incorrectDark gray, rough, and highly vesicular with a dull to slightly glassy luster; hardness about 5–6 Mohs. The visible holes are gas bubbles preserved as the lava cooled; crystal structure is fine-grained and mostly too small to see.
Identified More igneous →
Explore Scoria (vesicular basalt) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray, rough, and highly vesicular with a dull to slightly glassy luster; hardness about 5–6 Mohs. The visible holes are gas bubbles preserved as the lava cooled; crystal structure is fine-grained and mostly too small to see.
Formation & geological history
Forms when gas-rich basaltic lava rapidly cools at or near the surface, trapping bubbles. It may form during recent eruptions or in older volcanic deposits; the specimen’s age cannot be determined from the image.
Uses & applications
Used as lightweight aggregate, drainage material, landscaping stone, and sometimes abrasive or decorative material.
Geological facts
Scoria is often less dense than solid basalt, though it is generally heavier than pumice. Its vesicles distinguish it from many dense volcanic rocks.
Field identification & locations
Look for a dark color, abundant rounded cavities, and a rough surface; common near basaltic volcanoes and cinder cones worldwide. The image is consistent with scoria, but cannot confirm composition or locality.
