Purple clay
Look for small grains within an otherwise smooth brown surface. Xu Xiutang describes this combination in Zhongguo Zisha: the granular effect is more apparent at a broken section. Observe an existing exposed edge if available; do not damage a pot to identify it. Neither brown colour nor a few grains proves zini or its mine.
On this page
How the surface is made
The books separate the prepared clay from its finished surface. Crushing, sieving and mixing affect the body; a horn mingzhen smooths the vessel before firing. A smooth wall can therefore coexist with visible grains. These workshop descriptions do not measure the pores of a finished pot.
What the measurements establish
Hou and colleagues compared raw clays from Huanglongshan, Zhangzhu and Guangde using X-ray fluorescence, X-ray diffraction and microscopy. Their abstract distinguishes the distribution of quartz and clay aggregates in the Huanglongshan sample. It does not let us identify the internal structure of an untested pot from its surface. The older manuals give differently defined shrinkage statements; no combined range is presented here.
What to ask next
Describe the colour, sheen and visible grains separately. Then ask for the clay supplier or batch record, preparation and firing record, and any surface treatment. Composition needs a named, tested sample; a photograph cannot supply it.
Standards#
| Standard | Clause | What it covers | Sources |
|---|---|---|---|
| GB/T 10816-2024 紫砂陶器 | record | Recommended national standard for zisha ware, issued 2024-12-31, in force 2025-07-01, replacing GB/T 10816-2008. | 4 |
| GB/T 10816-2024 紫砂陶器 | 1 (scope); foreword | Scope speaks of a fine-textured, iron-rich special clay and covers classification, technical requirements, inspection and labelling of products. The foreword says the 2008 lead and cadmium release requirements were removed from this edition. Read through a commercial English rendering of the front matter only; clauses 5 onward were not seen. | 5 |
In other traditions#
- Written with the same characters as (from that entry) Banko ware Japan. Banko 紫泥 (shidei) shares its characters with Yixing zini. The paper read ties the shidei kyūsu method to Mino Akasaka Onko-yaki, not to Yixing.
Sources#
- 宜兴黄龙山紫砂原料特征的对比研究 (侯佳钰, 康葆强, 严建华, 苗建民), 陶瓷学报 2016, 37(4) ↗
- 孙荆、阮美玲：宜兴紫砂陶的显微结构和紫砂器的透气性（1993） ↗
- 陶博館季刊 2018/1–3月：宜興紫砂（紫砂泥特色） ↗
- GB/T 10816-2024 紫砂陶器 (Zisha ware), standard record ↗
- GB/T 10816-2024 English (scope and changes) ↗
- 王建中、范建军、唐伯年：《紫砂壶制作技法》。北京工艺美术出版社，1994。15–18 · PDF 23–26。
- 徐秀棠：《中国紫砂》。上海古籍出版社，1998，2000印刷。16–17 · PDF 47–48。
Status and editorial notes sources cited
Sources are listed below. Their presence does not certify every claim; source-specific interpretations and unresolved questions are identified in the text. This page has not received independent expert approval.
Accessed: 2026-11-02