Fig. 3

OM photos and SEM–BSE images of light greenish blue glaze cross section: a, b the hole glaze, a □C linear patterns resembling earthworm-walking patterns, i.e. the area without corrosion; □E and J corrosion area; c, d corresponding to Fig. 1a □C; e, f corresponding to Fig. 1a □E, dendritic pits after crystals corrosion(where the black arrow pointing to), cracks passing through the crystals, g, h and i enlarged images corresponding to Fig. 1f □G, small holes (where the black arrow pointing to) in crystals; j, k corresponding to Fig. 1a □J, dendritic pits and holes, unmelted quartz grains (Q) and cracks