Materials Seashells Natural seashells (clam, scallop, oyster, or snail shells work best) Shells should be clean, dry, and deep enough to hold liquid Small tray, bowl, or egg carton (to keep shells upright) Crystal Solution Borax powder (laundry aisle) Very hot water (near boiling; adult supervision required) Food coloring for raspberry–plum tones Red food coloring (base) Purple food coloring (depth) Optional: a tiny drop of blue for deeper plum tones Tools Heat-safe measuring cup or bowl Spoon T