title: Microscopic analysis of "iron spot" on blue-and-white porcelain from Jingdezhen imperial kiln in early Ming dynasty (14th-15th century).
abstract: "Sumali," as an imported cobalt ore from overseas, was a sort of precious and valuable pigment used for imperial kilns only, which produces characteristic "iron spot" to blue-and-white porcelain in early Ming Dynasty (A.D. 14th-15th century). Although there were some old studies on it, the morphology and formation of iron spot has not been fully investigated and understood. Therefore, five selected samples with typical spot from Jingdezhen imperial kiln in Ming Yongle periods (A.D. 1403-1424) were analyzed by various microscopic analysis including 3D digital microscope, SEM-EDS and EPMA. According to SEM images, samples can be divided into three groups: un-reflected "iron spot" without crystals, un-reflected "iron spot" with crystals and reflected "iron spot" with crystals. Furthermore, 3D micro-images revealed that "iron spots" separate out dendritic or snow-shaped crystals of iron only on and parallel to the surface of glaze for which "iron spot" show strong metallic luster. Combining with microscopic observation and microanalysis on crystallization and non-crystallization areas, it indicates that firing oxygen concentration is the ultimate causation of forming reflective iron spot which has a shallower distribution below the surface and limits crystals growing down. More details about characters of "iron spot" used "Sumali" were found and provided new clues to coloration, formation mechanism and porcelain producing technology of imperial kiln from 14th to 15th centuries of China.
authors: Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China.|Department of Archaeology and Anthropology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors: Wenxuan
authors: W
authors: Wang
authors: Department of Archaeology and Anthropology, University of Chinese Academy of Sciences, Beijing, 100049, China. jzhu@ucas.ac.cn.
authors: Jian
authors: J
authors: Zhu
authors: Institute of Ancient Ceramic, Jingdezhen Ceramic Institute, Jingdezhen, 333001, China.
authors: Jianxin
authors: J
authors: Jiang
authors: Jiangxi Provincial Institute of Cultural Relics and Archaeology, Nanchang, 330008, China.
authors: Changqing
authors: C
authors: Xu
authors: Institute of Ancient Ceramic, Jingdezhen Ceramic Institute, Jingdezhen, 333001, China.
authors: Shurong
authors: S
authors: Wu
authors: Jiangxi Provincial Institute of Cultural Relics and Archaeology, Nanchang, 330008, China.
authors: Li
authors: L
authors: Guan
authors: Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China.
authors: Zhaoxia
authors: Z
authors: Zhang
authors: School of Cultural Heritage, Northwest University, Xi'an, 710069, China.
authors: Menglei
authors: M
authors: Wu
authors: Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China.
authors: Jingnan
authors: J
authors: Du
keywords: Sumali; blue-and-white porcelain; iron spot; microstructure