made from stones harvested specifically for inkstone-making. Different stones yield different quality ink; as such, the material of an inkstone is critical to its functionality. Inkstones made from the stones of specific quarries, and from specific caves within those quarries, are highly sought out by collectors. Four Famous Inkstones Four kinds of Chinese inkstones are especially noted in inkstone art history and are popularly known as the "Four Famous Inkstones". Duan inkstones () are produced in Zhaoqing, Guangdong Province, and got its name from Duan Prefecture that governed the city during the Tang Dynasty. Duan stone is a volcanic tuff, commonly of a purple to a purple-red color. There are various distinctive markings, due to various rock materials imbedded in the stone, that create unique designs and stone eyes (inclusions) which were traditionally valued in China. A green variety of the stone was mined in the Song Dynasty. Duan inkstones are carefully categorized by the mines (k'eng) from which the raw stone was excavated. Particular mines were open only for discrete periods in history. For example, the Mazukeng mine was originally opened in the Qianlong reign (1736-1795), although reopened in modern times. She inkstones () come from She County (Anhui Province) and Wuyuan County (Jiangxi Province). Both counties were under jurisdiction of the ancient She Prefecture of Huizhou during the Tang Dynasty when the She inkstone was first made. This stone is a variety of slate and like Duan stone is categorized by the various mines from which the stone was obtained historically. It has a black color and also displays a variety of gold-like markings. She inkstones were first used during the Tang Dynasty. Tao(he) inkstones () are made from the stones found at the bottom of the Tao River in Gansu Province. These inkstones were first used during the Song Dynasty and became rapidly desired. It bears distinct markings such as bands of ripples with varying shades. The stone is crystalline and looks like jade. These stones have become increasingly rare and are difficult to find. It can easily be confused with a green Duan stone, but can be distinguished by its crystalline nature. Chengni inkstones () are ceramic-manufactured inkstones. This process began in the Tang Dynasty and is said to have originated in Luoyang, Henan. Usage Traditional Chinese ink is solidified into inksticks. Usually, some water is applied onto the inkstone (by means of a dropper to