Barium copper silicate

Description

A general name for either a blue (BaCuSi4O10) or purple (BaCuSi2O6) pigment found in paints and ceramic glazes on Chinese artifacts from the Han dynasty, 208 BCE - 220 CE.

Synonyms and Related Terms

Han blue; Han purple; Chinese blue; Chinese purple; silicato de bario y cobre (Esp.); silicato di rame e bario (It.)

Physical and Chemical Properties

• The purple is destroyed by dilute acids with some effervescence.
• The blue is acid-resistant.
• Both colors are strongly birefringent under crossed polars.
• Refractive Index = 1.72-1.74 (purple); 1.593-1.633 (blue)

Resources and Citations

• E.West FitzHugh, L.Zycherman "A Purple Barium Copper Silicate Pigment from Early China" Studies in Conservation 37:145-154, 1992.

• E.West FitzHugh, L.Zycherman "An Early Man-made Blue Pigment from China - Barium Copper Silicate" Studies in Conservation 28:15-23, 1983.

• Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, Pigment Compendium, Elsevier Butterworth-Heinemann, Oxford, 2004