I have also seen similar centerpieces that use epsom salts instead of sugar. You could also sprinkle a mix of pearls/gems. Sand (or sugar), faux pearls, a 3 candle. An easy DIY wedding centerpiece idea.
My grandma always dyed eggs with onion peels--that's how they did it back in the day! We made some last year but struggled with keeping the onion peel on the egg. This looks like an easier alternative.