Scoria

Dark, bubble-filled lava that piles up as cinder cones. Larger holes and heavier than pumice.

Scoria specimen — Photo: ScoriaPumice, CC0, via Wikimedia Commons

How to identify scoria

Black to rusty red.
Full of large, rounded holes.
Light for its size but sinks in water.
Rough, crunchy texture.

Often confused with

Pumice
Pumice is pale, finer-bubbled and floats.
Compare side by side
Basalt
Basalt is mostly solid with only some holes.
Compare side by side

Where it's found

Sunset Crater, Arizona
Mauna Kea, Hawaii
Chaîne des Puys, France

Uses

Landscaping 'lava rock', grill briquettes and road grit.

Rock tumbling

Not suitable for tumbling.

Did you know?

The red color comes from iron oxidizing while the lava is still hot.

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