The pottery-making tradition in the Yixing region has a long history spanning thousands of years, dating back to the Neolithic period four to five thousand years ago. The abundant clay mineral resources and the long history of pottery production established a unique natural material foundation for the rise and development of Yixing purple clay pottery. Purple clay is a special mineral earth contained within the interlayer clay and tender clay of Yixing's utilitarian pottery clay. It is primarily composed of quartz, clay minerals, hydromuscovite, and hematite. It possesses excellent plasticity and exhibits distinct differences in color and finished texture from ceramic raw materials in other regions. It has become world-renowned through the advancement and development of purple clay craftsmanship. Purple clay, because it is separated from the interlayer clay and tender clay of utilitarian pottery clay, has the alternative name "clay within clay, mud within mud." Purple clay can be mainly divided into three types: purple clay, Benshan green clay, and red clay. Purple clay accounts for 3%–5% of interlayer clay mineral deposits. Since ancient times, there has been a saying: "Emerging from various mountains, its veins often shift favorably. What is produced here may suddenly be found in another vein—truly the mountain spirits govern this. Yet all must be dug dozens of zhang deep to obtain it." Mining is extremely difficult. ## Huanglong Mountain Purple Clay Mine Regarding the mining of purple clay, by the Ming dynasty, the locations of various mineral deposits had been preliminarily identified, and a series of rich ore-selection experiences had been mastered. *Yangxian Ming Hu Xi* records: "Stone yellow clay comes from Zhaozhuang Mountain—it is the stone essence that has not yet been touched by wind and sun. When fired, it transforms into vermilion color. Sky blue clay comes from Tangzhu; when fired, it transforms into dark liver color. Moreover, within its interlayer there is..."[1] --- [1] (Ming) Zhou Gaoqi, *Yangxian Ming Hu Xi*, in Han Qilou (ed.), *Modern Translation of Ancient Purple Clay Texts* (Beijing: Beijing Publishing House, January 2011), p. 7.