"Such a unique rock, and guess who's there? Me! Take a look at how the various minerals are mingled together, and then observe the numerous individual crystals that are growing together and interconnecting. As the melted, liquid mass of rock consolidated and cooled, these crystals developed.
Tiny crystals indicate rapid cooling. It is referred to as an igneous rock. Igneous simply means to start a fire or the ignition of a vehicle. All igneous rocks previously underwent melting under intense pressure and heat."
I rock was previously completely molten and extremely hot. Large crystals indicate a slow cooling process that gave the crystals time to develop.
These are the kinds of rocks that are created by erupting volcanoes and gushing fissures. When exposed to the relatively cool temperature of the atmosphere, the magma, which is known as lava when molten rock erupts on the surface, cools and solidifies practically instantaneously.
in intrusive the crystals are big but in extrusive the crystals are comparatively small
INTRUSIVE!!
Igneous rock that is extrusive or volcanic is created when magma cools above (or very close to) the Earth's surface. These are the kinds of rocks that are created by erupting volcanoes and gushing fissures.