What is the primary form of rock that results from the cooling of lava?

The primary form of rock that results from the cooling of lava is igneous rock. When lava erupts from a volcano and cools, it solidifies to form igneous rock, which can be either extrusive or intrusive. Extrusive igneous rocks solidify quickly when lava cools on the Earth's surface, leading to a fine-grained texture. Intrusive igneous rocks, on the other hand, form when magma cools slowly beneath the Earth’s surface, resulting in a coarse-grained texture.

This distinction is based on the cooling process of molten rock material. Igneous rock is characterized by its mineral composition and texture, which are directly influenced by the rate and environment of cooling. Understanding this process is crucial in geology and helps in recognizing different types of rocks based on their formation.