igneous
Scoria (Red Lava Rock)
Extrusive Vesicular Basalt / Andesite
Dark red to reddish-brown color, highly vesicular (porous) texture, low density, hardness around 5 to 6 on the Mohs scale, earthy to dull luster, amorphous or fine-grained matrix.
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Physical properties
Dark red to reddish-brown color, highly vesicular (porous) texture, low density, hardness around 5 to 6 on the Mohs scale, earthy to dull luster, amorphous or fine-grained matrix.
Formation & geological history
Formed during explosive volcanic eruptions when gas-rich basaltic or andesitic lava is ejected into the air and cools rapidly, trapping expanding gas bubbles inside.
Uses & applications
Widely used in landscaping, gas grills (heat retention), drainage, lightweight aggregate in concrete, and decorative garden beds.
Geological facts
Because scoria cools so fast, minerals don't have time to form large crystals. The red color comes from the oxidation of iron in the lava while it was still hot and exposed to oxygen.
Field identification & locations
Easily identified by its deep red color, rough irregular surface, and sponge-like vesicular texture. Commonly found in volcanic regions, near cinder cones, and sold at home and garden centers.
