No.4 Mine Benshan Lüni
Beautifully soft in appearance, with an often equally soft pastel yellow hue, benshan lüni is a less commonly used, yet classic Yixing clay originating from the famous Huanglongshan (Huanglong Mountain).
Benshan or “original mountain” refers to clay mined from Huanglong Mountain. Lüni or “green clay” is so named for the color of the ore that has a green-grey color. Lüni is usually mined from 1. a thin layer between zini or between zini and another clay (sometimes called “clay in clay”); 2. a thin (a few cm thick) layer underneath a layer of quartz. The first type is a light yellow when fired and has a higher shrink rate during firing. The second type has a relatively darker color and a lower shrink rate. The firing temperature for benshan lüni is 1150C to 1250C, and the average shrink rate is 12%.
Layers of ore found in the Taixi Mine, with a thin layer of benshan lüni visible.
Taken from the book宜兴紫砂矿料 by 朱泽伟 等 Yixing Zisha Mineral Material by Zhu Zewei et al.
No. 4 Mine
The No. 4 Mine in Huanglong Mountain opened in 1972 and closed in 1997. The mine sits on the southwest side of the mountain. The mine penetrates deeper than most into Huanglongshan, in some spots reaching as deep as 80m. A report from 1987 shows that only 0.012% of the ore mined contains lüni. Aside from lüni, dicaoqing mined from the site also enjoys a reputation for quality.
Lüni Rarity
Lüni is only mined from the layers of ore mentioned above. Even when we include lüni mined from areas outside Huanglong Mountain, lüni is still only a very small percentage of the total amount of zisha mined in Yixing. Since the No. 4 Mine was officially closed in the 1990s, the only available clay and ore in the market comes from private collections.
Click here to read more about Benshan Lüni and Duanni.
References
宜兴紫砂矿料 by 朱泽伟 等 Yixing Zisha Mineral Material by Zhu Zewei et al.
阳羡茗砂土 by 刘玉林 等 YangXian MingShaTu by Liu Yulin et al.