Ink stone, pen, ink and paper are the traditional Four Treasures of the Study in China, and they are the necessary tools for China's calligraphy. The inkstone is not only the stationery of the study, but also a rare collection of literati in past dynasties because of its solid nature and immortality. The materials of inkstone are rich and varied. Besides Duanyan, Rolling Stone, Taoheshi, Chengnishi, Xugong, Yishui, Songshi, Kistler and Jushi, there are dozens of kinds of jade inkstones, jade miscellaneous stone inkstones, tile inkstones, lacquer sand inkstones, iron inkstones and porcelain inkstones.