What is the most common type of rock on Mars?

The most common type of rock on Mars is basalt. Basalt is a volcanic rock that is formed from the cooling of lava. Basalt is dark colored and has a fine-grained texture. It is composed mainly of pyroxene, plagioclase feldspar, and olivine.

The reason basalt is so common on Mars is because the planet's surface is covered by vast lava plains that were formed by volcanic activity billions of years ago. These lava plains cover about 70% of the planet's surface.

In addition to basalt, Mars also has other types of rocks such as sedimentary rocks, which are formed by the accumulation of materials such as sand, silt, and clay. There are also igneous rocks, which are formed from the cooling of magma, and metamorphic rocks, which are formed from the alteration of existing rocks by heat and pressure.