Honestly, this one probably shouldn't have been posted. Other hammers look much more detailed and worthy, but figuring out the major aspects of the handle was a challenge I felt was accomplished...given some reinterpretation. The same goes for the celtic knot...even if that was kickstarted by a useful plugin.
Eight months later, I followed a wonderful hammer tutorial by Chris Plush and CG Masters. It was surprisingly difficult to find one for Mjölnir that was made for beginners, so their style was absolutely appreciated. It would've been nice to achieve these results from scratch, but it'd be a disservice to these guys to not pass their expertise down. Please check out their work.