Yixing County, northwest of Shanghai, has been producing pottery with its famous "purple sand" clay, or zisha, since the Sung Dynasty (960-1279). But Yixing's fame (pronounced "ee-shing") really begins during the early Ming Dynasty (1279-1644) when local potters invented the teapot for steeping loose leaf tea.
Although most Yixing teapots are extremely small and crafted into unique shapes, meant for the Chinese tea ceremony, ours are simple, medium-sized teapots suitable for every day brewing.
Yixing teapots develop a rich patina with continued use, so don't use soap to clean. Just rinse out and air dry. (The information in black from http://www.indigotea.com/)