I just realised that I have never seen or used it, neither crude oil of course, but there are more variants of it than this natural mineral that powers a lot of the world.
As a child, I used to live alongside a heritage steam railway in the south of England. Much of the engineering/restoration works was accessible, along with huge sections of the way. I'd quite often find lumps of Welsh Steam Coal that had fallen off the engines. It has a very peculiar and distinctive (yet strangely pleasant) smell in its unburnt form.