Request for Chinese character identification

[SilverK]

Hi, I have this rather nice Chinese double-skinned napkin ring, but I can't read the character and can't establish whether it is a maker's mark or a fineness mark - I don't even know for certain if it is the right way up! It doesn't help that the mark isn't complete. I've had a look on the web and can't find anything similar, so I'm hoping that someone on the forum can help. Thank you.