A viewer just pointed this website out to me. Badali Jewelry. They have a whole line of jewelry that features our favorite ancient evil cephelopod. There are rings, earrings, necklaces, and even cufflinks with the Great Old One's face on them. They seem to all be available in sterling silver and gold.
Here's the part I thought was really cool. On the back of one of these pendants, they write "Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn". Now that's classy.