The type of rock primarily formed from liquid magma is igneous rock. When magma cools and solidifies, it can create various types of igneous rocks, which are categorized into two main groups: intrusive (or plutonic) and extrusive (or volcanic). Intrusive igneous rocks, such as granite, form when magma cools slowly beneath the Earth's surface, allowing large crystals to develop. In contrast, extrusive rocks, like basalt, form from lava that cools quickly on the surface, resulting in smaller crystals. These rocks provide valuable information about Earth's geological processes and are often used as building materials and decorative stones.