The necklace chain is very thin, but I don't think it'll break.  The pendant is about the size of a quarter.  It's heavier than I expected.  The big difference between the photo and the one that I received is it's purple.  Not a little bit purple but an amethyst purple, I'd never describe it as blue or black.  It's still a very nice piece and I'm still going to gift it to my cousin but without a doubt the stone is not black.