igneous
Vesicular Basalt
Extrusive Basalt (Mafic Silicate)
Hardness: 5-6 Mohs. Color: dark grey to black. Luster: dull to sub-metallic. Structure: vesiculated/porous (scoriaceous). Composition: primarily plagioclase feldspar and pyroxene.
- Hardness
- 5-6 Mohs
- Color
- dark grey to black
- Luster
- dull to sub-metallic
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Physical properties
Hardness: 5-6 Mohs. Color: dark grey to black. Luster: dull to sub-metallic. Structure: vesiculated/porous (scoriaceous). Composition: primarily plagioclase feldspar and pyroxene.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at the Earth's surface. The small holes (vesicles) are created by gas bubbles trapped in the cooling lava.
Uses & applications
Used in landscaping (lava rock), construction aggregate, railroad ballast, and as an abrasive in 'stone-washed' denim production.
Geological facts
Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. It is also extremely common on the Moon and Mars.
Field identification & locations
Identify by its dark color, heavy weight (high specific gravity), and the presence of small pits or vesicles. It is often found in volcanic fields or near ancient rift zones.
