Chemistry anyone?

[ownage overdose]

Help will be much appreciated.
I just need some Brief examples of

One naturally occurring mixture that is separated industrially into purer substances.

Here is the example that the teacher gave us [ we are not allowed to use this / BITCH ].
The magnetic molecules used to attract Ghiadia molecules in water refinement to make the water pure.

Website links, examples or just anything useful much appreciated.

N.B Go into detail if you wish.
~ Thank you in advance.