How does an igneous rock form???

Question

I know its made of lava, but how does it go from magma to a rock?

Answer 1

Igneous rocks form by the cooling of magma (molten rock material beneath the surface) or lava (molten rock material extruded onto the surface). Magma which originates at depths as great as 200 kilometers below the surface consists primarily of elements found in silicate minerals along with gases, notably water vapor. Because the molten material is less dense than the surrounding solidified rock, it works its way toward the surface where it flows out onto the surface as lava.

EM.12 Granite, an intrusive igneous rock.

Cooling of the magma initiates the crystallization of elements contained within the molten rock. Usually, cooling does not take place at the same rate throughout the entire mass. As it cools, numerous small crystal develop and then ions are added around these centers of growth. Once the crystals grow enough for their edges to meet, growth ceases and crystallization commences in another part of the mass. Over time the magma cools into a solidified rock of interlocking crystals. The rate of cooling determines the degree to which crystals can grow. Those that form by slow cooling have large crystals and are described as being coarse-grained. Fine-gained igneous rocks form by more rapidly cooling when the molten material is exposed at the surface. As a result, crystals don't have a chance to grow very large.

Answer 2

When lava or magma cools, it forms igneous rocks. When it cools on the surface from lava, they are called extrusive rocks. When magma cools beneath the surface, it tends to cool much slower, and they are called intrusive rocks. If you mean exactly HOW it goes from liquid to solid, it is because as it cools certain elements reach their crystallization points and solidify, the same way any element goes from liquid to solid.