Phase-Separated Glaze Microstructure in Ru-Type Celadon: Scientific Evidence from Microscopic Imaging and Comparison with Official Song Dynasty Standards

Abstract: This article presents high-magnification photographic evidence of phase-separated and crystalline microstructures in the glaze of a Ru-type celadon vessel. The study draws comparison with published scientific findings on Ru yao glaze (notably Pei Shi et al., 2020; Palace Museum reports, 2023). Microscopic features such as dense phase separation, light-scattering structures, and intercrystalline textures are matched against diagnostic patterns found in authentic Northern Song official kiln samples. The photographic evidence is supplemented by an expert commentary and referenced analysis. A citation to the author’s printed scientific encyclopedia (Dronova, 2016, p. 48) is included.

中文简介(Chinese Abstract): 本文通过显微图像展示了一件“类汝窑”青瓷器物的釉层微结构特征。图像清晰地揭示了釉层中的相分离结构、微晶体和气泡夹杂,均与北宋汝窑官方瓷器的典型工艺特征高度一致。文章结合了2020年Pei Shi等人关于汝瓷釉色形成机制的研究成果,并参照2023年故宫博物院的科学报告进行比对。研究证实该器物釉层具有符合米氏散射条件的纳米结构,是形成天青色泽和柔和光感的物理基础。此外,文中引用了作者所著的《中国古代瓷器鉴定》一书(2016年,第48页),进一步加强归属判断。

Figure 1. Macro Craquelure Network with Wide Linear Fissures

The glaze shows a dense pattern of intersecting linear craquelure typical of Northern Song Ru ware. The cracks are broad and unglazed inside, confirming differential cooling and stress within a thick glaze layer.

Comparative Reference: "Ru yao often exhibits wide and clearly visible crackle lines due to a thick and viscous glaze layer" (故宫博物院, 2023, p. 412).

Figure 2. Subsurface Blurring and Phase Field

The glaze surface shows a subtle clouding effect with internal color modulation, consistent with early phase-separated textures.

Comparative Reference: "The Tianqing glaze of Ru yao demonstrates depth and haze due to phase separation in the amorphous matrix" (Pei Shi et al., 2020, p. 20949).

Figure 3. Crystalline Cluster with Embedded Air Bubbles

Observed is a microscopic crystalline field with circular pits and vesicles. Such features are indicative of a semi-glass phase with entrapped gases during cooling.

Comparative Reference: "The interaction of crystallites and gas pockets forms a structural texture contributing to translucency and softness in Ru glaze" (故宫博物院, 2023, p. 409).

Figure 4. Microporous Field with Circular Crystallites

Micro-imaging reveals compact clusters of circular, low-contrast crystallites throughout the glaze body.

Comparative Reference: "Ru yao glaze is populated by dense microparticles formed during slow cooling and contributes to bluish opalescence" (Pei Shi et al., 2020, p. 20949).

Figure 5. Dense Microtexture of Phase-Separated Glaze Matrix

The texture reveals a high concentration of minute, amorphous clusters consistent with a phase-separated state.

Comparative Reference: "A number of crystallites and phase-separated domains meet the condition for Mie scattering" (Pei Shi et al., 2020, p. 20950).

Figure 6. Transition Zone Between Glaze and Porcelain Body

The image captures the gradient between the reddish ceramic body and the glassy glaze layer, with observable infiltration and bonding.

Comparative Reference: "Ru-type glazes infiltrate slightly into the ceramic body, producing a seamless yet slightly diffused junction" (故宫博物院, 2023, p. 406).

Scientific Note on Mie Scattering in Ru Glaze

Microscopic imaging shows that the Ru-type glaze contains crystallites and phase-separated zones whose size is comparable to visible light wavelengths (typically 0.1–1 micrometer). This satisfies the physical conditions for Mie scattering—a phenomenon where such structures disperse light in a soft, pearlescent way, producing depth, glow, and a bluish "heavenly" tone typical of Tianqing glaze.

"A number of crystallites and phase-separated domains meet the condition for Mie scattering" — Pei Shi et al., 2020, p. 20950

Conclusion: The glaze of the observed Ru-type vessel shows all hallmarks of authentic Northern Song Ru yao glaze: macro-craquelure, dense phase separation, vesicles, internal haze, and phase-domain light scattering. These observations are visually and structurally consistent with Palace Museum scientific records and peer-reviewed findings. Reference to p. 48 of N.D. Dronova’s 2016 encyclopedia further anchors the attribution.

Suggested Citation: Dronova, N.D. (2025). Phase-Separated Glaze Microstructure in Ru-Type Celadon: Scientific Evidence from Microscopic Imaging and Comparison with Official Song Dynasty Standards. Zenodo. DOI: to be assigned.

Related Publication: Dronova, N.D. (2016). Что надо знать о старинном китайском фарфоре [What One Must Know About Ancient Chinese Porcelain]. Moscow: Tipografia KEM. ISBN: 978-5-9908782-6-6, p. 48.

Keywords: Ru yao, Song dynasty celadon, phase-separated glaze, Tianqing glaze, Ru ware, Pei Shi, Mie scattering, Northern Song kilns, microscopic imaging, optical opalescence

关键词(Chinese Keywords): 汝窑、天青釉、北宋青瓷、相分离结构、微晶体、米氏散射、故宫博物院、显微图像、结构色、青瓷鉴定