Scaly silica particles having a laminated structure, consisting essentially of secondary particles of foliar silica, each formed by a plurality of flaky primary particles of scaly silica which are overlaid one on another and aligned face-to-face in parallel with one another, said secondary particles being present independent of one another. Electrical signals may be generated utilizing HPTs that detect the optical signals. A message including the segment of sensor data is sent to a second processing element.