Infinity Symbol Necklace

*sigh* The ghosts of boyfriends past...LOL. This was given to me by an old boyfriend. I live in the country. There are very few jewelers in the area. I just haven't had the time to take it in to see what this necklace is or is not. I can say the chain passes the magnet test (not magnetic) but no stamp. That's all I know. Is it real? Is it costume? I just don't know. I am listing as if it's just costume for now. If I'm motivated and learn otherwise, I will update this listing.