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.
Easy Sand Candles- Pay tribute to the Stars and Stripes (emphasis on the stripes). Red, white, and blue bands of sand dress up votive candles to make flickering lights that are cheerful and fun. via Martha Stewart Living