An inkstone depicting poet Li Bai drunk. [Photo provided to China Daily]

And together with the brushes, ink and rice paper, inkstones are considered one of the "four treasures" of a Chinese scholar.

Yang's collection shows various types of inkstones from almost all Chinese dynasties.

"Inkstones are one of my passions," says Yang.

"I consider them as a representation of ancient Chinese civilization and a cross-cultural bridge, especially when curators introduce them to international audiences."