Microstructure from Hongwu Reign

    We investigated 1 shard sample from Hongwu reign, which is from big plate painted with banana tree and bamboos in the garden. The shard is with length 36cm, width 27cm, and thickness 1cm.

    With naked eyes, we can see that the iron spots with various sizes on the shard big plate 021 appeared red-brown color.

1 microstructure of iron spots

    There are various sizes of iron spots. Very often, surrounding the iron spots, there exist one transitional zone with translucent dark brown color. And most of the iron spots appeared with red-brown color. Actually, there are two types of crystals can be seen on the iron spots. One type appeared red-brown color , which imbedded in the silver color glaze  under the dark field microscope. The other type appeared grey under the light microscope and most of them distributed on the red-brown color crystal.

2 glaze on the surface

    There are only few big bubbles >100µm sparkly distributed among the small bubbles. The density of the bubble is >200 per mm².

    Similar to the glaze of Yuan samples, the glaze showed crater structure. Compared to the Yuan samples, the crater structure on the Hongwu porcelain shard is more obvious and more densely (possible because of the more densely distributed small bubble).