What is the most common of the fine-grained igneous rocks?

1 Answer
Jun 29, 2016

Basalt.

Explanation:

Basalt is a dark-colored, fine-grained, igneous rock. It typically forms as an extrusive (quickly cooling, above ground) rock. Basalt is most commonly found in cooled lava flows and comprises almost all of the ocean floor. Below is a picture of vessicular basalt at Sunset Crater in Arizona, USA:

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Courtesy of: Jim Stuby; Obtained from: https://en.wikipedia.org/wiki/Basalt; Reused under: Public Domain