igneous
Basalt
Mafic Volcanic Rock
Hardness: 6 (Mohs scale), Color: Dark grey to black, Luster: Dull/Sub-metallic, Structure: Aphanitic (fine-grained), Specific Gravity: 2.8 - 3.0
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Physical properties
Hardness: 6 (Mohs scale), Color: Dark grey to black, Luster: Dull/Sub-metallic, Structure: Aphanitic (fine-grained), Specific Gravity: 2.8 - 3.0
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or very near the surface of a terrestrial planet or a moon.
Uses & applications
Used primarily in construction (crushed stone, asphalt aggregate), road base, and as decorative landscape stone.
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 found on the Moon and Mars.
Field identification & locations
Identify by its dark color, fine grain, and heavy weight relative to its size. Commonly found in volcanic regions and flow fields.
