In order to provide some extra fairy-tale shine to many of the shoes worn in Cinderella, the Wardrobe Department are adding individual Swarovski crystals. These provide more sparkle than sequins, and refract the light rather than simply reflecting it.
The crystals are attached to the shoes using a process called hot-stoning. Each one is in turn picked up with a device similar to a soldering iron. This heats and melts a layer of glue on the underside of the crystal without affecting the stone itself, allowing you to stick it to the fabric of the shoe.