A pair of stamps in celebration of the 40th anniversary of the establishment of diplomatic ties between China and Portugal is issued in Portugal. [Photo/Xinhua]

In celebration of the 40th anniversary of the establishment of diplomatic ties between China and Portugal, Portugal Post has issued a pair of stamps featuring local teapots.

The new pair of stamps, released on Feb 8, consists of a €0.53 stamp depicting a traditional Portuguese silver teapot and a €0.91 stamp showing a well-known Chinese Yixing zisha teapot. They were designed by Elizabete Fonseca from Portugal.

Zisha, or purple clay, comes from deep in the mountains near the city of Yixing in Wuxi, Jiangsu province. The clay contains many minerals, such as iron and quartz, which help to create the perfect teapot by keeping the water hot, helping the tea to infuse properly and to "breathe" thanks to its porous nature, which brings out the flavor and fragrance.

Yixing zisha teapots have been exported to Europe since the 17th century and are considered the world's finest.

One stamp features China's well-known Yixing zisha teapot. [Photo/Xinhua]

The teapot printed on the stamp was made by Yixing zisha master Wang Yinxian, bears the name "Jiu Tou Nan Gua Ti Liang", and features a pumpkin-shape and vines spiraling upwards on the handle.

It is the second time China and Portugal have cooperated to issue stamps. The first time was also during a celebration of the traditional Chinese New Year in Portugal.