In its oxide or silicate form, silicon is used to make concrete, bricks, glass, ceramics, and soap. Silicon metal is also the base material for making silicones used in such products as synthetic oils, caulks and sealers, and anti-foaming agents.
Intrusive igneous rocks crystallize below Earth's surface, and the slow cooling that occurs there allows large crystals to form. Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite, and peridotite. Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals.
IGNEOUS ROCKS are formed from the solidification of molten rock. Most of the Earth is composed of igneous rock. There are 2 major types of igneous rocks; intrusive igneous rocks, and extrusive igneous rocks.INTRUSIVE IGNEOUS ROCKS solidify beneath the Earth's surface.Because the magma cools over a relatively long period of time, Intrusive igneous rocks tend to have large mineral crystals that give the rock a rough granular texture.NTRUSIVE IGNEOUS ROCKS solidify beneath the Earth's surface. Because the magma cools over a relatively long period of time, Intrusive igneous rocks tend to have large mineral crystals that give the rock a rough granular texture.