This is a high-footed black pottery cup from the late Neolithic period in China. It measures 10 centimeters wide and 13 centimeters high. Despite being excavated around 2000 BC, it has been polished and still retains its luster, indicating advanced techniques of reduction firing were used at the time. It is extremely valuable that it hasn't broken, even though it's only 1 millimeter thick. It is considered a high-ranking piece among black pottery, known as "eggshell pottery," and is typical of the Longshan culture. It may not look like much, but similar pieces from the same period are housed in museums like the Metropolitan Museum of Art. Thank you.