Why not! This uncommon category of Sonic merchandise will feature metal items made specifically as jewelry. Stuff like rubber bracelets or plastic dog-tags that are half accessory half 'toy like collectible' don't really count. Metal collectibles like this are great, since most are immune to aging problems...plus, it's always better when you can decorate yourself with even more Sonic stuff!
Here's a solo better look at their figural Shadow pendant. (He appears on page 1 on their preview group shot) Of course, they've done another great job with this one, you can tell right away he has a fist and an open hand. They also catch the details of the red tongue area of the shoes, the red area on each stripe and the detail under the shoes. This is all difficult stuff to do on such a small space, and to be able to do it with a series of really tiny gemstones.
This is another of those 'well where would you wear it' type of items but...given infinite money...I would have it.
Is he a Sonic fan? Was it a paid ad (because it is known he enjoys advertising things) ? None the less, it's interesting to see someone with it outside of like the movie premiers where you know its all just promotion by actors. Screencap by All The Smoke