The material of purple clay pot is purple clay mineral soil, composed of purple mud, green mud and red mud three basic mud, collectively known as purple clay mud.
The raw material of purple sand is coarse-grained clay, which, like the porcelain clay of Jingdezhen and Longquan kilns, belongs to the type of Kaolin - quartz - mica, but has higher iron and silicon content.
There are three main seeds in color: one is purplish red and light purple, called "purple sand mud", the naked eye can be seen containing mica micro material, after burning for purplish black or purple brown; A grayish white or grayish green, called "mud", after burning for light gray or grayish yellow; These clay, yixing Dingshu town of huanglongshan are contained, purple clay is the most abundant, green clay is relatively rare. Using these clay to fire purple ware has the following advantages:
1. The raw material of purple sand has been settled and refined with good plasticity, small shrinkage rate and large firing range in the firing process, and the product is not easy to be deformed.
2. The water absorption of purple sand is less than 2%, indicating that its porosity is between ordinary pottery and porcelain. There are a lot of aggregates in the raw material of purple sand, and there are closed pores in the aggregates. When the agglomerates are sintered, they shrink greatly, and a layer of intermittent pores is formed around them, most of which are open pores, and the apparent porosity is about 5%. A vessel of this texture can be used to make tea with excellent color, aroma and taste. Used for planting flowers, with good air permeability and drainage, not easy to rot.
3. The slime molecules are arranged in a scaly structure, which is different from the particle structure of general ceramic slime. Therefore, the purple sand product is good in hot and cold, low thermal conductivity, when used as a tea set, touch not hot, cold winter season boiling water injection and fire frying is not easy to crack, better than a kind of porcelain.
4. It can be burned into dozens of colors, such as begonia red, purple sand, sunflower yellow, dark green, white sand, light ink, aloes, aquite, flash, grape purple, pomegranate skin, pear skin, bean green, new copper green, etc., all with the natural color of raw materials, become elegant and plain decoration of purple sand ware.