igneous
Scoria
Vesicular Mafic Igneous Rock
Hardness of 5-6 on the Mohs scale, typically brown, reddish-brown, or black in color, dull luster, aphanitic (fine-grained) with abundant vesicles (air bubbles), and a specific gravity around 1.0-2.0 (can often float in water temporarily).
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Physical properties
Hardness of 5-6 on the Mohs scale, typically brown, reddish-brown, or black in color, dull luster, aphanitic (fine-grained) with abundant vesicles (air bubbles), and a specific gravity around 1.0-2.0 (can often float in water temporarily).
Formation & geological history
Formed when gas-rich mafic or intermediate lava erupts from a volcano and cools rapidly, trapping gas bubbles within the solidifying rock. This geological process typically occurs in volcanic fields and cinder cones.
Uses & applications
Used in landscaping, lightweight aggregate in concrete, drainage systems, gas barbecue grills, and as a natural abrasive for skincare.
Geological facts
Scoria is often confused with pumice, but scoria is denser, darker in color, and has larger, more distinct vesicles with thicker walls, whereas pumice is light-colored and floats easily.
Field identification & locations
Easily identified by its rough, vesicular 'cinders' texture and dark or reddish coloration. Commonly found near volcanic regions, cinder cones, and basaltic lava flows worldwide.
