Snow Queen

An evil troll ("called the devil") makes a magic mirror that has the power to distort the appearance of things reflected in it. It fails to reflect all the good and beautiful aspects of people and things while it magnifies all the bad and ugly aspects so that they look even worse than they really are. The devil teaches a "devil school," and the devil and his pupils delight in taking the mirror throughout the world to distort everyone and everything. They enjoy how the mirror makes the loveliest landscapes look like "boiled spinach". They then want to carry the mirror into Heaven with the idea of making fools of the angels and God, but the higher they lift it, the more the mirror grins and shakes with delight. It shakes so much that it slips from their grasp and falls back to earth where it shatters into billions of pieces — some no larger than a grain of sand. These splinters are blown around and get into people's hearts and eyes, making their hearts frozen like blocks of ice and their eyes like the troll-mirror itself, only seeing the bad and ugly in people and things.
from Wikipedia The Snow Queen by Hans Christian Andersen About the Mirror and Its Pieces