When everyone first starts playing with purple Clay teapots, they know nothing about the colorful varieties of purple clay. Then they gradually learn about types like purple clay, duan clay, red clay, and so on. At first, they think they've become proficient, but then they discover names like purple eggplant clay, old purple clay, red skin Dragon, black star soil, golden duan, and moreā¦ which leaves them even more confused. I dare say that most enthusiasts are still at this stage: constantly exploring and collecting an endless variety of purple clay types. However, if you continue to delve deeper, you'll find that all the different types of clay are just derivatives or coexisting clays of the initial few types. They're only given different names due to differences in the color of the ore, the location of the mine, and the final color of the finished product.
1. Purple clay includes types like bottom groove clear (Dicaoqing) and old purple clay. The color range primarily spans from brownish yellow, brownish red, to chocolate colors. When assessing whether it's good quality material, pay attention to the particles. Personally, I believe that relatively correct purple clay materials will usually have a grainy feel, even if the slurry is fine and the burnishing is excellent. They often contain black dots (Iron) and lighter spots, and especially new pots have a dim luster, indicating good mineral pigments and excellent oiliness. If these characteristics are present, it's likely reliable.
2. Other types of clay include red skin dragon, red clear water, and red clay. Their color is mainly brick red and typically not too deep or bright. Note that these should not be confused with red clay (zhuni). These often have silvery speckles, and their tactile quality is similar to purple clay, with a strong sandiness. Good quality clay may not be as oily as some high-quality purple clays initially, but after long-term use, the color becomes brighter and more vibrant.
3. Red clay (zhuni) can be quite complex. Regardless of whether it's Zhaozhuang or small coal mine zhuni, there are some common characteristics among good quality zhuni. High-quality zhuni has a smooth, rosy hue, appearing as orange or crimson. The clay is very fine, feeling like a baby's skin. Additionally, good zhuni has a lively clay nature, making tea taste better, and the clay color appears lustrous and ruddy. However, honestly speaking, due to the naturally smooth characteristic of zhuni teapots, the difference between well-maintained and poorly maintained ones isn't particularly significant.
4. Original green mountain green clay typically requires high-temperature firing to prevent blackening. Its color ranges from pear-skin to light yellow with a green tinge, and it contains black particle dots. There is very little high-quality pure original green clay. Pure material has two distinctive features: one is its elegant, light color, being pale yellow rather than earthy or golden yellow. Second, after soaking and maintenance, the material becomes smoother and more jade-like compared to high-quality purple clay, giving it a unique texture.
5. Duan clay has a wide color range, including golden yellow, bright yellow, earthy yellow, brownish yellow, and green. Nowadays, most duan clay is a blend of purple clay and original green, sometimes mixed with red clay. The color is determined by the ratio of these materials and the Kiln temperature. Duan clay has the richest grainy texture of all the materials. It's difficult to maintain, but it enhances the flavor of tea very well. Furthermore, duan clay is the least likely to be faked among all the materials, and personally, I think it's a very suitable and reliable type of clay.
In summary, good quality material is the foundation of purple clay. There are many nuances and theories surrounding it. After handling so many teapots, I still believe that clay is the body, and form is the soul. As long as the craftsmanship is up to par, the material won't be poor. A potter who takes the time to craft a teapot will definitely put effort into selecting the clay, much like someone who wants to write seriously wouldn't hesitate to invest in good xuan paper.