easy-to-make plaster-cloth spheres. Wrap plaster-cloth strips (from a crafts store) around a balloon, following the directions on the plaster-cloth package. Leave open spaces as you wrap. When dry, remove the balloon and use a crafts knife to cut an opening for inserting the light. Place sphere over an orange or white battery-operated votive. Set your spheres on clear glass cake stands or similar displays.
Opal - The cause of the brilliant play of colors in opal was an enigma until relatively recently. Scanning electron microscope studies show that opals consist of transparent spheres of silica that are tightly packed. The voids or spaces between the spheres contain air or water. The regular arrangement of spheres acts as a diffraction grating, breaking visible white light into separate colors.