In terms of materials, its materials are very rich, including clay, porcelain, bronze, jade, crystal, tortoise shell, pine, agate, glass, lacquer, bamboo, cloisonne and so on. Its patterns are even more colorful, such as sapphire blue, Hong Jun, emerald green, black gold, lotus green, goose yellow, figures, landscapes, flowers and birds, cordyceps and so on.
"Try asking," wrote Xiao Zhi of Tibet Bowl. "There is no water in the bowl, how to dye the ink and how to brush it?" Inkstone is stone, and stone can refine gold and silver, so inkstone is "gold"; Paper is made of vegetation and can belong to "wood"; Ink is smoked by pine smoke and belongs to fire; Brushes come from sheep, rabbits, mice and wolves. This animal lives in soil, so it belongs to "soil".
Only Four Treasures of the Study is short of water. If the kettle is used as water, there are all kinds of kettles with five elements of fire, water and soil in Jin Mu, which are also called Shuicheng and Yandi. In ancient times, they were called "water injection". Its main function is to add water to inkstone, which first appeared in Qin and Han Dynasties. Its shapes are varied and ever-changing, but most of them are conformal and pictographic, and some are round, flat or vertical.