I think it's great you are considering the necklace. It's bold without being over-the-top. I think the contrast of the dark to gold metal against your skin works really well and you have a slender neck that shows it off very nicely.
I can also see the necklace working well for a transition to casual -- tank top with jeans.
I can also see the necklace working well for a transition to casual -- tank top with jeans.