Science: Igneous Rocks?

Question

When Magma cools down slowly it has more time to grow larger crystals
when magma cools down quick it has small crystals
can you please tell more information i can add to that?

Answer 1

You could mention that if, as a melt solidifies the temperature stays at the same level for a length of time, some crystals are given a chance to grow larger than they normally would, so the resulting rock has extra large crystals in a finer matrix . These are known as porphyries, the crystals themselves are known as phenocrysts ( for example Shap granite from the lake district in England, which has phenocrysts of orthoclase feldspar in a finer matrix )
There is some good info here on igneous rocks

Answer 2

You could mention that you need lots of the right elements in roughly the right proportions in the magma for crystals to grow large. Elements that are quite rare such as Zirconium only tend to form small crystals e.g. Zircon (zirconium silicate).
Having water present in magma helps as it helps elements freely move around (so they can get to where they need to be).
The biggest crystals grow in rocks called pegmatites. I've seen a single crystal 10 METRES across !

Answer 3

There are magma chambers that sometimes have certain crystals form that are heavier than the magma and therefore fall to the bottom of the magma chamber forming an ore deposit.

Answer 4

Igneous rocks are also called ire rocks, They are formed either underground or above ground.. It is formed underground when Magma are trapped in small pockets, and as these pockets cool down.. they become igneous rocks. Above the ground, it is formed when a volcano errupts and the magma becomes lava. and when it cools down.. it become igneous rocks... An example or igneous rocks are granite and obsidian.

Answer 5

igneous rocks can be subject to metamorphasism.