A Chinese inkstone and an ink stick with Chinese characters in gold, that read jīn bù huàn (金不换), which translates as ‘no exchange even for gold’ and refers to the type of pine-soot it is made from. This kind of stick was used for ink by the pupils in the old-style Chinese private schools since the 18th century.

It is still the most popular ink in today's Chinese elementary schools where calligraphy is a required course for new generations. The design of the stick is simple, fit right for the hands of students and can be easily stored in a pencil box. In addition though unrelated, jīn bù huàn is also the name for a kind of milkwort, known by the scientific name Polygala glomerata, which is widely distributed in southern China, where it is used in traditional herbal medicine.