GENERAL KNOWLEDGE

Detailed explanation-1: -There are two basic types: (a) intrusive igneous rocks such as diorite, gabbro, granite, peridotite and pegmatite that solidify below Earth’s surface; and (b) extrusive igneous rocks such as andesite, basalt, obsidian, pumice, rhyolite and scoria that solidify on or above Earth’s surface.

Detailed explanation-2: -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.

Detailed explanation-3: -Andesite is the volcanic equivalent of diorite. It consists of the plagioclase feldspar minerals andesine and oligoclase, together with one or more dark, ferromagnesian minerals such as pyroxene and biotite.