Whether they are fired from a mine, an aerial shell, or a rocket heading, firefly stars produce a cloud of orange charcoal-sparks, with many silver flickering sparks flashing off and on, resembling fireflies on a hot summer night. The effect is a beautiful but subtle one, so when a device containing firefly stars is fired, no other devices should be fired immediately afterward, until the many-seconds-long firefly display has had time to finish. Firefly-star shells are great when fired as volleys in a display, and then allowing the twinkling stars to fall gently, and to display completely before any other...