Ok, I watched season 2 again and cleos locket is BLUE. I saw it up close when lewis put it back on her on the final episode of season 2.

here's my proof

here it looks white right?
link
link
link
in here it's clearly a blue


link
link

as so you know, I do know emma gave cleo her locket in season 1. But these are clearly season 2 and season 3!!