igneous
Scoria (Lava Rock)
Scoria
Hardness: 5-6 (Mohs scale), Color: Reddish-brown to black, Luster: Dull/earthy, Structure: Vesicular (full of air bubbles), Specific Gravity: Low (often floats briefly/lightweight)
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Physical properties
Hardness: 5-6 (Mohs scale), Color: Reddish-brown to black, Luster: Dull/earthy, Structure: Vesicular (full of air bubbles), Specific Gravity: Low (often floats briefly/lightweight)
Formation & geological history
Formed from gas-rich basaltic or andesitic magma cooling rapidly during a volcanic eruption, which traps gas bubbles as the rock solidifies.
Uses & applications
Used in landscaping, gas grills, high-temperature insulation, drainage systems, and as an abrasive in stone-washing jeans.
Geological facts
Scoria differs from pumice because it has larger vesicles and thicker cell walls, making it dense enough to usually sink in water, whereas pumice often floats.
Field identification & locations
Identify by its highly vesicular (bubbly) texture and reddish-brown color caused by the oxidation of iron. Common in volcanic fields like those in Iceland, Hawaii, and Italy.
