I love those people with incredible eyesight and not a little time on their hands, who took this still from Captain America: The Winter Soldier and noticed a teeny tiny little detail...
If you are still having trouble making out what that is, it's a delicate silver arrow on a necklace, and you can see her wearing it throughout the film.
An obvious reference to her relationship with Hawkeye, this is the kind of detail that makes me love Marvel even more. Also makes me want to own one of my own, because I'm one of those nerds who wants replicas of everything.
So I found it for you!
Actually, I found a surprising number of these little arrow necklaces in gold, rose gold and silver. I also found one or two in darker, more distressed finishes, usually called Katniss necklaces!
This particular one can be found here on Etsy.com (which is generally a fantastic place to dig up replicas and nerdy items). Now if you'll excuse me, it's time to get my credit card out!