Fig. 2

Raman spectra of the samples LY01 and LY02, laser wavelength 532 nm, output energy 50%. Baseline fitting was applied. a The spectrum of a purple particle of the LY02 sample corresponds to Chinese purple. b The spectrum of a light blue particle of the LY01 sample corresponds to Chinese purple and Chinese Blue. c The spectrum of a blue particle of the sample LY01 corresponds to Chinese Dark Blue. d Raman spectrum of crystals of BaSnSi₃O₉ contained in the LY02 sample (top) and of synthetic BaSnSi₃O₉ (bottom) (Chapter 3d)