igneous
Scoria
Vesicular Mafic Igneous Rock
Hardness of 5-6 on the Mohs scale, dark brown to black or reddish color, dull luster, aphanitic texture with numerous gas cavities (vesicles), specific gravity around 2.0-2.5.
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Physical properties
Hardness of 5-6 on the Mohs scale, dark brown to black or reddish color, dull luster, aphanitic texture with numerous gas cavities (vesicles), specific gravity around 2.0-2.5.
Formation & geological history
Formed through the rapid cooling of basaltic or intermediate lava that is rich in dissolved gases, typically associated with Strombolian volcanic eruptions.
Uses & applications
Used widely in landscaping, as a lightweight aggregate in concrete, in gas barbecue grills, and as a natural abrasive for personal care (foot pumice).
Geological facts
Scoria is similar to pumice, but it has larger vesicles, thicker vesicle walls, and a higher specific gravity, which usually causes it to sink in water.
Field identification & locations
Easily identified in the field by its dark color, heavy weight compared to pumice, and characteristic spongy, vesicular texture. Found worldwide near volcanic regions and cinder cones.
