igneous
Red Scoria
Vesicular Basalt (Fe – rich)
Hardness: 5–6 (Mohs); Color: Dark reddish-brown to bright red; Luster: Dull/Earthy; Structure: Highly vesicular (porous); Specific Gravity: 2.5–3.0 (though feels lighter due to air pockets).
- Hardness
- 5–6 (Mohs)
- Color
- Dark reddish-brown to bright red
- Luster
- Dull/Earthy
Identified More igneous →
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Physical properties
Hardness: 5–6 (Mohs); Color: Dark reddish-brown to bright red; Luster: Dull/Earthy; Structure: Highly vesicular (porous); Specific Gravity: 2.5–3.0 (though feels lighter due to air pockets).
Formation & geological history
Formed from gas-rich basaltic magma cooling rapidly at the Earth's surface during volcanic eruptions. The red color indicates oxidation of iron-rich minerals (like magnetite or olivine) during or after the eruption.
Uses & applications
Commonly used in landscaping, as a lightweight aggregate in concrete, for gas grill lava rocks, and in horticultural soil mixes for drainage.
Geological facts
Unlike pumice, scoria has thicker vesicle walls and is usually dense enough to sink in water. It is a primary component of many cinder cones found around the world.
Field identification & locations
Identified by its 'Swiss cheese' texture, rough surface, and deep red color. Frequently found in volcanic fields such as those in the Western United States, Iceland, and Italy.
