the outer crust isnt made of iron and nickle because thats what we are living and walking on.
please mark brainliest
Extrusive volcanic rocks are formed on the surface of the earth and cool relatively quickly from lava erupted from a volcano. The rapid cooling of lava on the surface does not allow for visible crystals to form. The crystals are minute and most can only be seen under a microscope. Basalt is an example of an extrusive igneous rock.
Intrusive igneous rocks are formed when magma cools within the crust. This magma cools slowly and so crystals develop in these rocks. Granite is an intrusive igneous rock.
There are multiple reasons for the variations in type, quality, and quantity in minerals, such as:
- place of formation, on the surface, or inside the ground and how deep inside.
- pressure; extremely important for the structure of the minerals as well as the mixing of mineral types.
- temperature; similar to the pressure, in fact in combination with it, affects the structure of the minerals.
- tectonic activity and volcanic activity; cause the other factors and are also responsible for the quantity of minerals.
