igneous
Scoria
Vesicular Basaltic Glass
Hardness: 5-6 (Mohs scale); Color: dark red, brown, or black; Luster: dull to vitreous; Structure: vesicular (porous); Specific gravity: 0.8-2.1 (some float on water briefly, but most sink).
- Hardness
- 5-6 (Mohs scale)
- Color
- dark red, brown, or black
- Luster
- dull to vitreous
Identified More igneous →
Explore Scoria in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-6 (Mohs scale); Color: dark red, brown, or black; Luster: dull to vitreous; Structure: vesicular (porous); Specific gravity: 0.8-2.1 (some float on water briefly, but most sink).
Formation & geological history
Formed from the rapid cooling of basaltic or andesitic magma containing high levels of dissolved gases which expand to create holes (vesicles). Commonly found in cinder cones and volcanic fields.
Uses & applications
Used extensively in landscaping, drainage systems, gas grills for heat retention, lightweight concrete manufacturing, and as abrasive traction for icy roads.
Geological facts
Scoria is often confused with pumice, but it is denser and has larger vesicles; it is the primary material that makes up cinder cone volcanoes.
Field identification & locations
Identify by its rough, sponge-like texture, dark color, and lightness relative to solid basalt. Commonly found in volcanic regions like Hawaii, Italy (Mount Etna), and the American Southwest.
