A locket containing David's baby hair which Laura Collins was wearing both in Episode #139 when she gained Vicki as an ally and when she burned to death in Phoenix. Burke found the locket after Laura burned to death in the fishing shack (192).
The locket was at one point owned by Josette Collins (the original mid-19th-century conception of Josette). It was passed down and Roger gave it to Laura as a wedding present.