Just Some Dude in Jersey
Chuckle! I've got a special football-sized rock in my garden that I have used since the early '80's to work on my Opel. Mainly I used it to boost the lifting height of my jack. It helped me do my first engine and leaf spring swaps back in 1990, which I did with nothing more than a small car jack(which I also still have and use constantly) and that rock. It's indestructable and has 6" diameter carving marks in it from when it was quarried. It must have been at the bottom of a drill hole in a rock face that then had been dynamited to quarry the rocks. I think it's basalt.
It's even got RED paint on it!