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.
Rocks that crystallize below the surface of the earth are known as intrusive or plutonic rock. Some examples of intrusive igneous features are dikes, sills, batholiths, and laccoliths. Click here to take a tour of some of the intrusive igneous formations found in Big Bend.ocks that crystallize above the surface of the earth are known as extrusive or volcanic rock. When volcanoes erupt and sheets of lava pour out across the surrounding area, the feature that is created is called a lava flow.