What kinds of famous inkstones are there?

Inkstone, also known as inkstone, is one of the traditional Chinese handicrafts. Inkstone, together with pen, ink and paper, is also called the traditional Four Treasures of the Study in China, and it is an essential tool for China's calligraphy. Inkstone materials are also widely used, among which Hongsi inkstone in Qingzhou, Shandong Province, Duanyan in Zhaoqing, Guangdong Province, She Yan in Guzhou (now Huangshan Mountain) in Anhui Province and Taohe inkstone in Zhuoni, Gansu Province are the most prominent, and they are called "four famous inkstones".