Fighting with various ways to make a tiara...anyone know if sugar gems (that I will make) would stick to a royal icing tiara? I'm kinda guessing no, and that it would also not support the weight...but I don't want to take the time (in short supply at the moment) to test it if someone already knows. Help? Thanks!

Hiya I made sugar 'droplets' for a cocacola can cake, with a tiny bit of water on the back and holding a few seconds they stuck just fine to air-dry fondant and gum paste, if your tiara is piped royal then you'll probably need a little dot of same coloured royal to stick it.
if you're going to use clear glaze don't spray till after you stick on the gems- they don't stick as well to glazed fondant plus a coat of glaze will help stop the gems going sticky in the humidity
HTH