igneous
Gabbro
Gabbro
Hardness of 6 on the Mohs scale, dark gray to black or dark green color, submetallic to dull luster, coarse-grained phaneritic crystal structure, no distinct cleavage, specific gravity ranges from 2.7 to 3.3.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black or dark green color, submetallic to dull luster, coarse-grained phaneritic crystal structure, no distinct cleavage, specific gravity ranges from 2.7 to 3.3.
Formation & geological history
Formed from the slow cooling of magnesium- and iron-rich magma beneath the Earth's surface, creating an intrusive igneous rock equivalent to basalt.
Uses & applications
Used in construction as crushed stone, dimension stone, architectural facing, countertops often sold under trade names like 'black granite', and monuments.
Geological facts
Gabbro makes up a large portion of the oceanic crust and is one of the most abundant rock types in the deep crust of the Earth.
Field identification & locations
Can be identified in the field by its dark color and visible interlocking crystals of plagioclase feldspar and pyroxene. Commonly found in layered intrusions and ophiolite complexes worldwide.
