Calcite is an aggregate of calcite, the color of which varies according to its purity. Impurities usually include bittern, silicic acid, clay, iron, and bitumen, giving rise to the names bitter lime, siliceous lime, earthy lime, iron-bearing lime, bituminous lime, and others. Some are produced by sedimentation or deposition of biological remains, and those rich in fossils are known as coral limestone, siliceous limestone, and foraminiferous limestone. Those with less bitter soil and iron are emphasized as cement materials and for sugar production, and their uses are wide. For ceramics, it is widely used as a raw material for lime glazes and calcareous ceramics, and was generally used as a fluxing agent for lime glazes after the middle of the Meiji period. The main production areas include Akasaka in Gifu Prefecture, Ehime Prefecture, Oita Prefecture, and Okayama Prefecture, etc. The lime for ceramics is gray in color and is generally called milk lime.
