An interesting question with a surprising answer. It would appear to be a Mark owned by the japanese company Noritake. A full explaination can be found at https://www.invaluable.com/blog/nor...ns a,exquisite, elegant ceramic pieces around. I haven't researched the Noritake page, although I have never previously noticed anything about RC Cutlery or Ceramics.
@Bakersgma I know it is not; but it is RC and it has a form of crown on it. The pertinent point is have you ever seen a Noritake Mark like that on the Invaluable page. I'm taking a punt that assuming Noritake ever issued under the RC symbol, they might have varied it, and that Noritake is a reasonable place from which to start researching if there is nothing else more relevant.