Devotion to one deity or another is a little bit of a touchy subject around here, so I won't go into that, but if you want to make an amber pendant with a rune on it, I don't think anyone would argue.

If it were me, I would start with something pre-polished like this and then either buy or borrow a rotary tool such as the Dremel in that link and carve it yourself. Fill with enamel or paint, you can find smaller quantities at a hobby store, to make it more visible. If you use a latex-based paint, you'll want to seal the whole bead with a polyproplene (sp?) or something similar. Then use the same tool or a drill to drill a small hole in it and put it on a cord, or you can find jewelry mounts on Amazon as well but they're going to be more "effeminate." With Amber, you'll want to use slow speed for carving and drilling as it could be a little more fragile. You could also find a pre-drilled bead and do the same thing, I saw some on Amazon doing that search that had reinforcing grommets out of stainless steel.

EDIT: If you're not keen to do all that work or want something more specific, there's a pendant from Jelling Dragon which is claimed to be based on a "Viking find from Sweden," looks like a mini-statue of the goddess and it only runs $24 in bronze or $42 in silver.