* Dark and Coarse-Grained: Gabbro is a dark-colored, coarse-grained igneous rock. The dark color comes from its high content of mafic minerals (rich in magnesium and iron).

* Intrusive: Gabbro is an intrusive rock, meaning it cooled and solidified beneath the Earth's surface. This slow cooling allows for the formation of larger mineral crystals, resulting in its coarse grain.

* Similar to Basalt: Gabbro and basalt have similar mineral compositions, primarily consisting of pyroxene, plagioclase feldspar, and sometimes olivine. The key difference is that basalt is extrusive (cools on the surface), leading to its fine-grained texture.

Other possibilities:

While gabbro is the most likely answer, other dark, coarse-grained intrusive rocks could be considered:

* Diorite: This rock has a similar composition to gabbro but contains more plagioclase feldspar.

* Peridotite: This rock is even darker than gabbro and is richer in olivine.

To accurately identify the rock, you would need to examine its mineral composition and texture more closely.