Here's why:
* Composition: Basalt is rich in magnesium (Mg) and iron (Fe), which are the defining characteristics of mafic rocks.
* Color: It's typically dark gray to black due to its high content of dark minerals like pyroxene and olivine.
* Texture: Basalt is often fine-grained, meaning its crystals are too small to be seen with the naked eye. This is because it cools quickly, giving the minerals little time to grow.
* Occurrence: Basalt is a common volcanic rock found on the ocean floor, in volcanic arcs, and in some continental settings.
Other examples of mafic rocks include:
* Gabbro: A coarse-grained, intrusive equivalent of basalt.
* Diabase: A fine-grained, intrusive rock that is similar to gabbro but has a more elongated grain structure.
Let me know if you'd like to explore any of these examples in more detail!