Green glaze, which is applied to the surface of earthenware, is made by adding minium to lye or silicic acid, and mixing it with iron for the pigment. Green-glazed tiles were excavated from royal palace sites such as Wolseong and Wolji, as well as the sites of Sachonwangsa Temple and Gameunsa Temple, which suggests that tiles of this type were used exclusively for royal palace buildings or large-scale temples built by the government. Double-layered lotus petals are the representative design of the convex roof-end tile of Unified Silla.