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Examples of extrusive igneous rocks include: Basalt : A dark, fine-grained rock, commonly found in oceanic crust. Andesite : Typically found in volcanic arcs associated with subduction zones.
Examples of intrusive igneous rocks are: diabase, diorite, gabbro, granite, pegmatite, and peridotite. Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals. Some cool so quickly that they form an amorphous glass.
igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of molten earth material. Igneous rocks constitute one of the three principal classes of rocks, the others being metamorphic and sedimentary.
Igneous rock (igneous from Latin igneus 'fiery'), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust.
The igneous rocks are one of the three main types of rock found on earth; the others are sedimentary rock and metamorphic rock. They are the hardest and heaviest rock on earth. They are also called the ‘new’ rocks or magmatic rocks.
Examples include basalt, rhyolite, and andesite. Obsidian is an example of an extrusive igneous rock that is amorphous or lacks crystalline structure. Properties and Characteristics of Igneous Rocks. Igneous rocks are typically hard and dense, resistant to weathering, and often exhibit a crystalline structure.
Types of Igneous Rocks. Igneous rocks are those that form via the process of melting and cooling. If they erupt from volcanoes onto the surface as lava, they are called extrusive rocks. By contrast, Intrusive rocks are formed from magma that cools underground.
The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is . magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet.
The mineral compositions of igneous rocks are usually described as being felsic, intermediate, mafic, or ultramafic (as examples, see Figure 4.7 and Figure 4.8). Felsic rocks are made of light-colored, low-density minerals such as quartz and feldspar.
News. Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface.