Non-destructive Raman spectroscopy has been used to study ancient ceramics. On the basis of spectral features characteristic to the microstructures, the composition and technological processing of ceramics in ancient times could be quantitatively determined. Ceramics are heterogeneous materials composed of grains of different phases, coated by different glazes containing various pigments. The question of reliability and representation of the Raman spectra recorded from the surface of glaze or on a section of shard is discussed. As an illustration, ancient (13–14th centuries) Vietnamese (proto)porcelains made at Ha Lan (Nam Ðinh) were studied with particular attention to the analysis of the SiO4-based glassy network: Spectral components of the Si–O stretching mode are analysed in terms of isolated (Q0), more or less associated (Q1, Q2, Q3) or fully-bonded (Q4) SiO4 tetrahedra. The results show the facility and reliability of Raman spectroscopy as a non-destructive technique suitable for discrimination between ancient ceramics and modern copies. Copyright © 2002 John Wiley & Sons, Ltd.