Black Glaze with Burnt Leaf Imprint from the Song Dynasty: Part II – Microscopic Analysis and Material Authentication

Author: Prof. Nona Dronova, PhD, DrSc, Expert in Chinese Ceramics and Glaze Diagnostics
Affiliation: Antique Porcelain Archive, ORCID: https://orcid.org/0009-0007-4867-9074
Zenodo Community: https://zenodo.org/communities/antique-porcelain-archive/

Abstract: This article presents the second part of the scientific study on a unique black-glazed Song dynasty vase bearing a burnt plant leaf imprint. While Part I provided typological context and visual diagnostics, this continuation focuses on high-magnification images and microscopic examination of the glaze, substrate, and embedded organic residue. The analysis confirms the authenticity of the object as a rare, large-scale ritual or kiln-sacrificial piece (yao xian qi 窑献器), fired under transitional oxidation conditions. This contribution also supports comparative research between genuine Song artifacts and later reproductions.

1. Introduction The presence of a naturally imprinted leaf beneath black glaze, preserved under thick glassy coating, poses both aesthetic and scientific significance. Such imprints are indicative of early experimental interactions between organic matter and high-fired glazes during the Song dynasty. This article documents five microscope images from the surface and subsurface zones of the glaze and presents an analysis of the craquelure, siliceous inclusions, carbonized organic content, and transitional glaze behavior.

2. Microscopic Image Analysis

Figure 1. Macro view of burnt leaf imprint under black glaze.
This macro-photograph captures the central motif of the vessel — a fully imprinted maple-like leaf trapped under a glassy black glaze. The sharp veins, color zoning from dark amber to carbonized black, and the peripheral craquelure indicate pre-glaze placement of the organic material and subsequent high-temperature vitrification.

Figure 2. Microscopic detail of crackle structure with fibrous residue.
The image shows a web of fine craquelure traversing the glaze. A translucent fibrous inclusion (bottom right) is likely an ash-transformed remnant of the original leaf. The crackle pattern follows thermal contraction paths typical of Song dynasty black-glazed wares.

Figure 3. Organic combustion residue with mineral-ash matrix.
This fragment reveals the darkened, porous zone with embedded silicate crystals and unreacted carbon deposits. The heterogeneous distribution supports a natural ash formation scenario, consistent with spontaneous combustion during firing rather than artificial application.

Figure 4. Crackle glaze network and burn imprint under magnification.
This zone highlights the interface between a burnt leaf region and the overlying glaze. The glaze displays glass-phase contraction, entrapment of impurities, and a smoky appearance with clear craquelure. No synthetic resins or surface additives are present.

Figure 5. Edge zone between oxidized slip and vitrified glaze with embedded mineral residues.
A close-up of the transition between the reddish body (oxidized slip) and the dark vitrified glaze. The silvery crystallized inclusion and ash-fused matrix confirm a pre-industrial firing process. The white fiber-like inclusion suggests ash mineralization under intense heat.

3. Conclusion All visual and microscopic features align with natural processes observed in genuine Song dynasty black-glazed ceramics. The glaze’s craquelure, optical depth, and organic entrapment support the object's authenticity. No indications of modern tampering or replication were found. The object's technical and symbolic characteristics suggest its use in ritual or sacrificial kiln contexts.

This study confirms the findings from Part I (Zenodo DOI: 10.5281/zenodo.16651600) and will serve as the foundation for further chemical analysis.

References:

1. Dronova, N.D. (2016). What One Should Know About Ancient Chinese Porcelain (in Russian). Moscow: Diamond Books. [Page 142: Photo of the same object published]

2. Dronova, N. (2025). Black Glaze with Burnt Leaf Imprint from the Song Dynasty: Part I – Typology and Context. Zenodo. https://doi.org/10.5281/zenodo.16651600

Keywords: Song dynasty ceramics, black glaze, burnt leaf imprint, glaze craquelure, microscopic glaze analysis, kiln sacrificial vessel, Chinese porcelain, ceramic authentication, siliceous inclusions, Antique Porcelain Archive

Chinese Summary (中文摘要): 本论文为《黑釉叶痕器》的第二部分,重点分析宋代黑釉瓷器中的叶片印痕在显微镜下的表现特征。通过五张高倍图像的观察,作者确认该器物的裂纹结构、玻璃化釉面和植物燃烧残留物均符合宋代高温烧制工艺的自然现象,未见现代仿制痕迹。器物应为祭器或试验性器皿,具有极高的科研与艺术价值。