For one-of-a-kind illumination, flex your mussels and cockle shells. As shown here, we used Beach-BarnArt Black Mussel Shells ($17 for 24, etsy.com) and Violet ClamShells each measuring 1/2" to 3/4" ($20 for 1 gal., buytheseaonline.com). Arrange them in concentric circles, and hot-glue them onto a basic wrought-iron hanging candle sconce—their pearlescent interiors will cast a special glow.
Paint disk gray; let dry completely. Using mussel-shell halves and small cockle shells, lay out your design on disk. (We created concentric circles, with cockles at center and mussels at edge.) When you're happy with it, hot-glue shells on, one at a time, working your way around. Let dry completely.
Affix one half of Velcro strip to center of wooden disk, and other to bar of the candle holder. Stick them together. Hang from hook.