The same structure as mica dust with the platelets an order of magnitude larger and tilted much further out of plane. Fewer flakes catch the light at any moment, and each one that does is big enough to read as a distinct flash. A mirror ball is that description built at a size you can walk up to: several hundred flat mirrors, each glued at its own angle, and at any instant only the handful whose normal happens to bisect you and a lamp are lit. It is the one specimen here whose structure you can count by eye.