WHAT IS IGNEOUS ROCK

Extrusive igneous rocks, also known as volcanic rocks, are formed at the crust's surface as a result of the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface.

Igneous rock or magmatic rock, is one of the three main <a class="mw-redirect" href="https://en.wikipedia.org/wiki/The_three_types_of_rocks" title="The three types of rocks">rock types</a>, the others being <a href="https://en.wikipedia.org/wiki/Sedimentary_rock" title="Sedimentary rock">sedimentary</a> and <a href="https://en.wikipedia.org/wiki/Metamorphic_rock" title="Metamorphic rock">metamorphic</a>. Igneous rock is formed through the cooling and solidification of <a href="https://en.wikipedia.org/wiki/Magma" title="Magma">magma</a> or <a href="https://en.wikipedia.org/wiki/Lava" title="Lava">lava</a>. The magma can be derived from <a href="https://en.wikipedia.org/wiki/Partial_melting" title="Partial melting">partial melts</a> of existing rocks in either a <a href="https://en.wikipedia.org/wiki/Terrestrial_planet" title="Terrestrial planet">planet</a>'s <a href="https://en.wikipedia.org/wiki/Mantle_(geology)" title="Mantle (geology)">mantle</a> or <a href="https://en.wikipedia.org/wiki/Crust_(geology)" title="Crust (geology)">crust</a>. Typically, the melting is caused by one or more of three processes: an increase in <a href="https://en.wikipedia.org/wiki/Temperature" title="Temperature">temperature</a>, a decrease in <a href="https://en.wikipedia.org/wiki/Pressure" title="Pressure">pressure</a>, or a change in composition. Solidification into rock occurs either below the surface as <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Intrusion" title="Intrusion">intrusive</a> rocks or on the surface as <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Extrusive_(geology)" title="Extrusive (geology)">extrusive</a> rocks.