Diamond Quiz

[Dyer, Sonia]

Olivier wrote:
>Sicne you asked the question, I've been thinking of  the Hope Diamond
> (which you can see at the Smithsonian in DC), but what troubled me is
> that I thought I would have remembered such a reference; now you say
>it is not named in the story, I obviously cound't remember an explicit
>reference. Now, I have no idea in which story it appears. Apparently
>it's a background detail.

It's definitely a sight gag!
HINT: It's in a story by an American author/artist.