how do intrusive and extrusive rocks differ?

Answer 1

Intrusive igneous rocks are formed from magma that cools and solidifies within the earth. Surrounded by pre-existing rock (called country rock), the magma cools slowly, and as a result these rocks are coarse grained. The mineral grains in such rocks can generally be identified with the naked eye.

Extrusive igneous rocks are formed at the Earth's surface .. Because lava cools and crystallizes rapidly on the surface, it is fine grained. If the cooling has been so rapid as to prevent the formation of even small crystals after extrusion, the resulting rock may be mostly glass (such as the rock obsidian).

Because the minerals are fine-grained, it is much more difficult to distinguish between the different types of extrusive igneous rocks than between different types of intrusive igneous rocks. Generally, the mineral constituents of fine-grained extrusive igneous rocks can only be determined by examination of thin sections of the rock under a microscope, so only an approximate classification can usually be made in the field.

Answer 2

Extrusive Rocks

Answer 3

Intrusive rocks cooled slowly below ground, with enough time for minerals to form. In an intrusive rock (e.g. granite), you can see differentiated minerals.

Extrusive rocks are formed by lava extruded onto the surface of the earth. They cool quickly and therefore the lava does not have time to form minerals. In an extrusive rock (e.g. basalt), you are less likely to find differentiated minerals.

Answer 4

intrusive-inside the earth extrusive-outsidethe earth

Answer 5

answer of 007 is brief. but
to be detailed...
extrusive rocks have no time to form..s...fine grain of minerals
intrusive rocks have large grain sizes of minerals..
and better crystalization.. so precious stones (like Jade, diamond..) formed