Igneous rock is formed through the cooling and solidification of magma or lava. They are granular in texture and are not found in the stratified form. They are devoid of any kind of fossils. Igneous rocks often have a co-relation with volcanic activities. Igneous rocks are hard for water to penetrate.
Igneous rock is found both in crystalline and non-crystalline form. They are also known as Primary rocks.
Igneous rocks are divided into two main categories-
(a) Plutonic or Intrusive rocks – formed when magma cools and crystallises slowly within the earth’s surface. Ex-granite.
(b) Volcanic or extrusive rocks are – granite, Gabbros, pegmatite, Basalt, Volcanic breccias etc.
