Misinformation online suggests that Jiangpo clay is not valid if it shows red hues within a yellow base; this has been passed around without any basis. Perhaps we could say that Jiangpo clay with a reddish hue in a predominantly red base is slightly superior to that with a reddish hue in a predominantly yellow base, which might be more appropriate.
The Jiangpo clay mine is primarily extracted from a small hill where Huanglong Mountain meets Qinglong Mountain, belonging to the shallow marker layer of minerals. The Jiangpo deposit is of the “chicken nest” type, meaning the formed mining areas are not fixed. They appear sporadically in scattered patches, typically ranging from a few centimeters to 20-30 centimeters thick.
Jiangpo clay is typically mined from two areas: one close to the face of Huanglong Mountain, where the natural color of the ore is a mix of red and yellow (the surface stones of Huanglong Mountain contain sulfur, hence the ore color is generally brownish-yellow). The other area is near the face of Qinglong Mountain, where the excavated ore is a mix of green and red (the surface stones of Qinglong Mountain have a higher content of calcium carbonate, so the ore color is usually greenish). In general, the quality of the clay closer to Huanglong Mountain is better than that near Qinglong Mountain.
Jiangpo clay from the area near Qinglong Mountain needs to undergo refinement before it can be made into clay, or it may produce ash explosions (related to the Qinglong Mountain clay mentioned earlier). In terms of color, the Jiangpo clay from the Huanglong Mountain side is slightly redder (what people commonly refer to as reddish-yellow); while the clay from the Qinglong Mountain side is slightly yellower (yellow with a red hue). The firing temperature range is very wide, from low temperature 1.5 to high temperature 3.5, resulting in different colors at different temperatures.
Therefore, some people mislead by saying that Jiangpo clay must have a reddish hue, and clay with a reddish hue within a yellow base is not Jiangpo clay. This is a one-sided view, as it depends on the deposit layer and the firing temperature.
Additionally, it's worth noting that making Jiangpo clay turn red is not particularly difficult. One simply needs to carefully select and refine the red mineral components from the deposit. However, such Jiangpo clay can be seen as more pure and valuable from another perspective (after all, there is less of it, and it requires more material and time…). As for the comparison of Tea brewing effects after such meticulous selection, I haven't thoroughly studied it yet. Perhaps I'll try it out and share my conclusions next time. But it can be confirmed that such a red color appears more luxurious and lustrous.