Red Scoria (Lava Rock)

Physical Properties

Hardness: 5-6 (Mohs scale); Color: Dark red to reddish-brown; Luster: Dull to earthy; Structure: Highly vesicular (pitted with gas bubbles); Specific Gravity: Relatively low/lightweight due to air pockets.

Formation & Geological History

Formed through the rapid cooling of basaltic or andesitic magma that is highly charged with volcanic gases. As the lava erupts, gases expand and escape, leaving behind a 'frothy' porous texture.

Uses & Applications

Commonly used in landscaping as decorative ground cover, as a high-temperature insulator in gas grills, in drainage systems, and as an additive in lightweight concrete.

Geological Facts

Scoria is often confused with pumice, but it is denser and sinks in water, whereas pumice floats. The red color is typically due to the oxidation of iron within the lava as it cools in an oxygen-rich environment.

Field Identification & Locations

Identify in the field by its sponge-like appearance, red color, and sharp, jagged edges. It is commonly found near volcanic cinder cones and basaltic flows.

Identified on: 4/13/2026

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