From the CRAFT Flickr pool, user truemirage writes:

“Fordite” is the rather tongue-in-cheek name given to this amazing multi-color material, which is really…..paint! Back when cars were sprayed rather than dipped, layers of paint would build up on the machinery. Some smart lapidarist decided to cut and polish a chunk as if it were a stone and thus was Fordite created. (A related variety called Dagenhamite comes from the auto factories in, you guessed it, Dagenham, England.)