touchstone

/ˈtʌt͡ʃstəʊn/

Etymology

From touch + stone.

touchstone means A surname. Lexicurio rates it Rare gem — a strength score of 76 out of 100.

name

A stone used to verify the quality of gold alloys by rubbing them in order to leave a visible trace.
A standard of comparison or evaluation.“Near-synonym: comparator”