There is no known historical or mythological object called the "Delphic Stone." It's possible you're thinking of something else.

Here are some possibilities:

* The Omphalos (Navel of the World): This was a sacred stone in the Temple of Apollo at Delphi. It was believed to be the center of the world and was often used as a reference point for pilgrims and travelers.

* The Sibyl's Oracle: The Sibyl of Delphi was a prophetess who spoke through the Delphic Oracle. Her pronouncements were often written on stone tablets, which could be considered a form of "Delphic Stone."

* The Tripod of Delphi: This three-legged stool was used by the Pythia, the priestess who delivered the oracle's pronouncements at Delphi. It was said to be placed over a chasm that emitted prophetic vapors.

Could you provide more context or details about the "Delphic Stone" you're referring to? I'd be happy to help further!