Metal Leaf is a micro-thin sheet of metal separated by pages of tissue paper. All through history in the world of decorative arts, gold leaf has played a very prominent role. Precious metals continue to exemplify quality and good taste. Mona Lisa leaf products and techniques make the leafing process fun and foolproof with satisfying results every time. 23 KT Gold Leaf is as pure as gold leaf can be made. Due to the micro thin nature of the leaf, there must be a small amount of a metal alloy added to hold the leaf together. 23 KT Gold Leaf does not have to be sealed, and can be used outdoors.