Celadon tea cup from the city of Longquan. At the bottom, the seal "青瓷 龙泉".
 
 
DID YOU KNOW ...?
Celadon or 青瓷 qīngcí is a kind of Chinese greenish ceramics (it can also be grayish, bluish). Traditionally, it was produced in the city of Longquan in the province of Zhejiang from the ninth century. Widely distributed in China during the Song dynasty.