My necklace hasn't broken yet, but as another review said, it's not a sturdy chain.  The watch itself is gorgeous, but mine was ticking when it arrived, and already seems to be losing a few minutes each day.... about 15min/24hr so far, and with no instructions or labeling of any kind, I have no idea if the battery can even BE changed.  It's a pretty piece, but don't rely on it as an actual timepiece.  The tassle was not to my liking, so I replaced it with a antiqued looking feather in a similar patina.

The globe is not glass, the half orbs on front and back are acrylic. The holder on which the watch swivels is plastic with a metal overlay (it feels light and flimsy).  The watch itself is heavy and very sturdy, though I don't see any way to change the battery, a definite downside.