"I always carry a piece to show the kids about pressure and evolutionary effects."
He blushed.
"Some always have questions and this is an easy demonstration."
He concealed the coal in his hands and pressed, vibrating them at the same time. There was a squeaking, squelching sound, and his hands blurred for a moment, then he shook them, shaking away some coal dust, and opened them, revealing a large diamond, half the size of his palm.