The positively charged white particles and negatively charged black particles react to changes in electrical current, moving to the display surface and coloring the surface. (visionect.com)
Here's the awesome paradigm shift: these dirty, black particles from the air will then be transformed into gems, set into rings. (treehugger.com)
Apply a charge to the spheres and they will flip one way - perhaps showing black particles. (phys.org)