Eu acho que isso é Furnace by Muriel Gray . A cena do carona é:
Josh saw her standing by her rucksack on the left of the narrow road. She’d seen him first, of course. It was hard to miss a truck. By her body language it was clear she wasn’t sure whether it was worth sticking out a thumb. As rides went, the one with the pick-up driver must have been the shortest in hitch-hiking history. She’d been dropped a good five miles away from the interstate junction and it didn’t look like she was pleased. Before he knew why, Josh was slowing up.
...
"Naw. I think it’s cool.’ She bounced again and then looked across at him. "I’m Griffin"
A história está de fato ligada à alquimia e, em particular, à descoberta da pedra filosofal no cenário improvável da cidade de mesmo nome Forno, na Virgínia.