25 sheets of gold or silver metal leaf, and the special glue for applying the leaf to all sorts of surfaces including paper, canvas, wood, stone, etc.
Brush the glue onto the surface exactly where you want the metal leaf to go. Let it dry for 10 minutes or so, until it is no longer wet, but still sticky. Apply the leaf on top of the glue. It is very fragile - if you're using a whole sheet, use the paper that's packaged between the sheets to transport it. Use a soft brush to tap the leaf onto the glue and to brush away any excess. Scraps of leaf can be saved and used for future projects.