Answer: Basalt
Explanation:
Basalt is a dark igneous rock that usually forms from lava flow. It is the most common rock at the bottom of the Earth's oceans where it underlines most basins which means that it, by extension, is the largest type of rock underlying the Earth's surface.
Basalt is phaneritic-rock as it forms from lava that has crystallized on or close to the Earth's surface and is made up of about 30% calcium-rich plagioclase feldspar, about 55% pyroxene, and about 15% olivine.