igneous
Basalt Pebble
Aphanitic Mafic Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic texture with microscopic crystals, and high specific gravity around 2.9.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic texture with microscopic crystals, and high specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Used in construction aggregates, railroad ballast, stone countertops, and landscaping.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms most of the lunar maria.
Field identification & locations
Identified by its dark color, heavy weight, and fine-grained texture, commonly found tumbled along riverbeds and ocean beaches.
