when you touch the stone is it cold, even if its in a hot place? If so that generally means its real. Even if its not its still gorgeous. def bidding, 11" chain wouldnt think of fitting me but chains can be replaced lol.
just like graham777 said if it cool to the touch its real if it hot out side put it out there for a hour and then get after a hour if its cool then its real i collect jade and no matter what they stay cool and the one i have on is cool and i have been out side in 90 degree weather allday