LAUSR

Abstract Porcelain that contains micrometer-sized e-Fe2O3, a promising advanced material with unique magnetic properties, has received growing attention these years. Herein, we discovered millimeter-sized unprecedented mullite-e-Fe2O3 clusters organized in a flower-like manner blooming on the Hare’s Fur Jian ware of the Song dynasty (960–1279 A.D.). They are composed of branches radiating from the center, petals growing along the branches, needles on both sides of the petals and reflective platforms distributed all over the flower. After a series of microscopic and spectroscopic characterizations, mullite and e-Fe2O3 were identified to be the main components, and a possible growth process was proposed. The residual quartz in the glaze, the relatively thin glaze on the edge of the bowl and the reducing firing environment were considered to be the main factors for its formation. These results provide a novel access toward the ancient ceramic technologies and inspirations on refractory mullite and magnetic material e-Fe2O3.