Kes' locket
A locket was a pendant that held a picture inside. According to Human tradition, it was meant to hold a photograph of a loved one.
Tom Paris gave Kes a locket for her second birthday in 2371. It cost him two weeks' worth of replicator rations and elicited strong feelings of jealousy from Neelix. Despite claiming to be cured of his jealousy, the Talaxian nevertheless compared Paris' token of affection with his, noting that the locket was replicated, while his Jiballian fudge cake was made from scratch. (VOY: "Twisted")
Sometime prior to 2375, Sarah Sisko had a locket with ancient Bajoran writing on it. That year, Joseph Sisko gave it to their son Benjamin Sisko, saying he wanted Ben to have it and Sarah would have wished the same. Its existence confused Joseph, as he didn't recall her ever mentioned Bajor to him. Jake Sisko then theorized that she didn't know it was Bajoran, or that a friend gave it to her as a gift. The writing was then translated as "Orb of the Emissary". (DS9: "Image in the Sand")