I've seen a few attempts to recreate the "Deep One" jewelry described in "The Shadow Over Innsmouth", but this is the first time I think the artist nailed it.
This is an absolutely beautiful piece that captures the alien nature of the Deep Ones while still being aesthetically pleasing. Browse around the gallery after the link and you'll find even more cool jewelry.
(As an aside, the reason I stumbled across this necklace is because my significant other insisted I was wrong about not being a "jewelry" person, as I posted last Thursday. So I spent about an hour trying to find pieces I thought were attractive before finally finding this one.)