Also kira, ummo, or unbo 雲母. Mica. Mica is a silicate mineral with a layered structure, whose crystals are often found in granite deposits. It is ground down to give a white powder which is mixed with sizing *dōsa 礬水 for an undercoat used on paper, silk, and wood before painting. A mica coating *kirabiki 雲母引 gives a smooth painting surface with a shiny finish. Mica powder is also used as a pigment *ganryō 顔料 in woodblock prints *ukiyo-e 浮世絵, and for paper decoration. In a technique known as kirazuri 雲母摺, the printing block is coated with paste nori 糊 or animal glue *nikawa 膠 and printed onto the paper. Mica is then sprinkled over the glue before it dries. Sometimes a red or grey layer is printed before applying the mica, producing a red or grey sheen.