igneous
Basalt Pebble
Aphanitic mafic extrusive rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, microcrystalline to cryptocrystalline structure, no visible cleavage, and high specific gravity around 2.9-3.0.
Identified More igneous →
Explore Basalt Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, microcrystalline to cryptocrystalline structure, no visible cleavage, and high specific gravity around 2.9-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, iron- and magnesium-rich lava flows at the Earth's surface, typically originating from volcanic activity.
Uses & applications
Utilized widely in construction as crushed aggregate for road bases, railroad ballast, and in the production of concrete and asphalt.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and is also found extensively in volcanic plains on the Moon and Mars.
Field identification & locations
Easily identified by its dark, fine-grained texture and heavy feel; commonly found rounded in riverbeds and along coastlines due to water erosion.
