igneous
Scoria
Scoriaceous Basalt
Hardness: 5-6 (Mohs scale), Color: Reddish-brown to dark black, Luster: Dull/Earthy, Structure: Vesicular (highly porous/holey), Specific gravity: 0.8-2.1 (lightweight)
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Physical properties
Hardness: 5-6 (Mohs scale), Color: Reddish-brown to dark black, Luster: Dull/Earthy, Structure: Vesicular (highly porous/holey), Specific gravity: 0.8-2.1 (lightweight)
Formation & geological history
Formed from gas-rich basaltic magma that cools rapidly during volcanic eruptions. The holes (vesicles) are created by trapped gas bubbles. Typically recent to Quaternary in age.
Uses & applications
Used in landscaping (lava rock), aquarium filtration, lightweight concrete, gas grills for heat retention, and road traction on ice.
Geological facts
Scoria is often mistaken for pumice; while both are volcanic, scoria has larger bubbles and thicker walls, making it denser than pumice. It will usually sink in water while pumice floats.
Field identification & locations
Identify by its reddish/black color and numerous large spherical or elongated bubbles. Usually found near cinder cones and volcanic vents. Lightweight but sharp to the touch.
