gabbro

n. volcanic rock which resembles granite

Gabbro (IPA: ) is a dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt. It is a plutonic rock, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass. The vast majority of the Earth's surface is underlain by gabbro within the oceanic crust, produced by basalt magmatism at mid-ocean ridges.
See more at Wikipedia.org...

Noun
1. one of a family of granular intrusive rocks
(hypernym) igneous rock

n. gabbro, volcanic rock which resembles granite

n. gabbro, volcanic rock which resembles granite