Han blue (also called Chinese blue) is a synthetic barium copper silicate pigment that was developed in China at least 2,000 years ago. Han purple and Han blue were used in ancient and imperial China from the Western Zhou period (1207-771 BC) until the end of the Han dynasty (c. 220 AD).

Han blue has the chemical formula BaCuSi4O10. In 1993, it was discovered to occur naturally as the rare mineral effenbergerite.

Han blue, like Han purple, has a layered structure with silicate forming the structural framework. However, Han blue is more stable because of structural features. It does not break down in dilute acids and becomes more bluish when ground.