Fairy dust

Fairy dust was a glowing, magical dust which appeared to be generated by some kinds of fairies.

The Strange and Wonderful Room's Anteroom was lit by a “chandelier” whose light source was actually a group of fairies who sat on the fixture. Their falling fairy dust created a magical pillar of cold white fire in the centre of the room, into which guests to the House could step to find themselves transported to the room of their choice. (PROSE: Our Strange and Wonderful House: The Anteroom)