Gold leaf is an ultra-thin sheet of gold, typically around 0.076 to 0.127 micrometers thick, used for decorative purposes and gilding. It's produced by rolling or hammering gold, often 22-karat yellow gold, into very thin sheets. These sheets are then applied to various surfaces, such as wood, metal, paper, or textiles, to create a gilded effect, adding a touch of luxury and opulence.