Scientific analysis of white porcelain unearthed from the Guifangzi and Gangyanzi kiln sites in the Helan Mountains reveals an unusual body composition characterized by high silica and low alumina. The contents of impurity elements such as iron and titanium are particularly low, with iron levels approaching the lowest known values in ancient Chinese ceramic bodies. The glaze composition shows certain similarities to that of the Lingwu kiln, as both belong to the high-temperature calcium glaze system; however, the contents of magnesium, manganese, phosphorus, iron, and titanium are significantly lower than those found in Lingwu white porcelain. The firing temperature of the white porcelain from Guifangzi and Gangyanzi is approximately 1250 °C, and the body is essentially sintered, with evident corrosion of residual quartz and, in some samples, a substantial presence of mullite crystals, indicating a higher firing quality than that of Lingwu kiln products. Due to the exceptionally low levels of iron and titanium impurities, the whiteness of these porcelains is remarkably high, meeting the traditional aesthetic preference for white ceramics in the Western Xia dynasty.

Keywords: Western Xia dynasty, Guifangzi kiln, Gangyanzi kiln, Lingwu kiln, White porcelain.