We call the liquid form of rock magma, in the same way that we call the liquid form of ice water.. In simple terms, the earth is just a large ball of magma which has crystallized into solid rock where it's exposed to the coldness of space.ecause granite is less dense than the seafloor basalt (s.g. 2.7), it tends to ride higher in the crust, and generally forms the major land masses. Most of the earth's major crustal plates are mixtures of both basalt and granite, as well as many other types of rock in lesser amounts.