igneous
Basalt River Stone
Extrusive Igneous Rock
Hardness of 6 on the Mohs scale, dark grey to black color, fine-grained aphanitic texture, dull to sub-metallic luster, specific gravity around 2.8-3.0.
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Physical properties
Hardness of 6 on the Mohs scale, dark grey to black color, fine-grained aphanitic texture, dull to sub-metallic 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.
Uses & applications
Used in construction, aggregate, cobblestones, and notably for hot stone massage therapy due to its heat-retention properties.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's oceans.
Field identification & locations
Smooth and rounded by water action in a riverbed or stream; identified by its dark, heavy, and fine-grained nature.
