What is oil commonly referred to?
Correct answer: Black gold

Aradlaw
I remember that from The Beverly Hillbillies theme song "black gold, Texas tea..."

Goodboy
What a different world it will be when its gone!

alderaanic
Aradlaw, Exactly what I was going to say. Was only a young kid when it was on UK TV but remember the opening song saying "Black Gold" & "Texas Tea"

Tasty Potato
I only knew this answer because of the Beverly Hillbillies

DkRatz72
Goodboy, perhaps... if oil (or a synthetic variant) isn't around you can say goodbye to commercial air travel as well as many other things. For the time being it's a necessary evil.

Danny
I'm going to start calling it liquid licorice, that's just plain funny.