igneous
Vesicular Basalt (Scoria)
Vesicular Basalt
Hardness: 5-6 (Mohs); Color: Dark brown, black, or reddish-brown; Luster: Dull/earthy; Crystal Structure: Aphanitic (fine-grained) with many vesicles (gas holes); Specific Gravity: 2.2-2.7
- Hardness
- 5-6 (Mohs)
- Color
- Dark brown, black, or reddish-brown
- Luster
- Dull/earthy
Identified More igneous →
Explore Vesicular Basalt (Scoria) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-6 (Mohs); Color: Dark brown, black, or reddish-brown; Luster: Dull/earthy; Crystal Structure: Aphanitic (fine-grained) with many vesicles (gas holes); Specific Gravity: 2.2-2.7
Formation & geological history
Formed from rapid cooling of gas-rich basaltic lava at the Earth's surface. The holes (vesicles) are created by trapped gas bubbles that escaped as the rock solidified. Common in volcanic regions.
Uses & applications
Used in landscaping for volcanic rock features, as road base, for gas grills (lava rocks), and sometimes in cement production.
Geological facts
Scoria is similar to pumice but is more dense and darker in color; unlike pumice, most scoria will sink in water because its vesicles are larger and less interconnected.
Field identification & locations
Identify by its 'Swiss cheese' appearance with many holes and its relatively light weight compared to solid basalt. Often found near cinder cones and shield volcanoes.
