igneous
Gabbro
Gabbro
AI-generated identification · may be incorrectHardness 6-7, dark gray to black or dark green color, massive structure, phaneritic texture, composed mainly of pyroxene and calcium-rich plagioclase
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Physical properties
Hardness 6-7, dark gray to black or dark green color, massive structure, phaneritic texture, composed mainly of pyroxene and calcium-rich plagioclase
Formation & geological history
Intrusive igneous rock formed by slow cooling of magnesium- and iron-rich magma deep beneath the Earth's surface
Uses & applications
Used as crushed stone for concrete aggregate, road base, and railroad ballast; sometimes cut and polished as 'black granite' for countertops and cemetery markers
Geological facts
Gabbro is the intrusive equivalent of basalt. The oceanic crust is mostly made of gabbro and basalt.
Field identification & locations
Identify by its dark color, coarse-grained texture (crystals visible to the naked eye), and high density. Commonly found in large batholiths and dikes.
