igneous
Basalt Pebble
Extrusive Igneous Rock
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, dull luster, specific gravity around 2.8 - 3.0
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, dull luster, specific gravity around 2.8 - 3.0
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the surface of a planet or moon, often through volcanic eruptions.
Uses & applications
Used in construction, aggregate for roads, railroad ballast, and sometimes in landscaping or decorative stones.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms much of the volcanic islands.
Field identification & locations
Found widely across volcanic regions globally; identified by its dark, fine-grained appearance and heavy density.
