Examination of pigments by using FT-THz

Terahertz (THz) spectra of Azurite, which is copper based natural mineral, were measured by a Fourier transform spectroscopy (FT-THz) in the 3-20 THz region and by a terahertz time-domain spectroscopy (THz-TDS) in the 0.1-3.6 THz region. We observed finger print spectra of pigments and discuss the influence of grain size of pigment. The issues of specimen for quantitative analyses are also discussed.