igneous
Scoria
Scoriaceous Basalt
Hardness: 5-6 (Mohs scale); Color: dark red, brown, or black; Luster: dull; Structure: highly vesicular (pitted with holes); Cleavage: none; Specific Gravity: varies (often floats in water temporarily due to air pockets)
- Hardness
- 5-6 (Mohs scale)
- Color
- dark red, brown, or black
- Luster
- dull
Identified More igneous →
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Physical properties
Hardness: 5-6 (Mohs scale); Color: dark red, brown, or black; Luster: dull; Structure: highly vesicular (pitted with holes); Cleavage: none; Specific Gravity: varies (often floats in water temporarily due to air pockets)
Formation & geological history
Formed from extrusive volcanic activity where gas is trapped in cooling lava, usually basaltic or andesitic in composition. Found in volcanic regions near cinder cones.
Uses & applications
Used in landscaping (lava rock), high-temperature insulation, drainage systems, gas grill stones, and lightweight concrete aggregates.
Geological facts
Unlike pumice, which is also vesicular, scoria is denser and usually darker in color. It is often the primary component of cinder cones, which are the simplest type of volcano.
Field identification & locations
Identify by its 'Swiss cheese' appearance and lightweight feel relative to size. Commonly found in tectonic plate boundaries and hotspots like Hawaii, Iceland, or the American Southwest.
