Some factories in Xupu, Hunan, Chaozhou, Guangdong, etc. use ordinary clay such as clay, loess and black soil, and add chemical raw materials such as "iron red powder" and manganese dioxide for dyeing to prepare and process the raw material mud of the liner. The so-called "purple sand liner" is made by stamping and firing this raw mud.

Sand has been used in cooking and drinking utensils for more than 1000 years. Modern scientific detection and analysis have proved that it does not contain any harmful elements. According to the records in the pot of purple sand soup and porridge in Compendium of Materia Medica, it is proved that natural and high-quality five-color stone grease is one of the important raw materials of high-quality purple sand mud and purple sand ore. The efficacy of five-color stone grease determines the health care function of purple sand products, and the quality of five-color stone grease determines the quality of purple sand products. The following compendium of materia medica is a description of five-color stone grease, an important raw material of purple sand.

"Compendium of Materia Medica" records five-color stone grease: a paste-like thing condensed in a piece called grease, which is very viscous in nature and very good for solid economy and body use. Practice has proved that natural five-color stone oil is one of the important natural raw materials of natural purple sand products.

Shi Ming's essence is like stone and sticky, hence the name five fingers. There are different types of bluestone grease, yellow stone grease, black stone grease, white stone grease and red stone grease, which are collectively called "five colors and five fats". Halloysitum rubrum is the most commonly used medicine, white stone is rarely used, and bluestone, Huangshi and Blackstone are not used as medicine.

Smell: All five oils are sweet, flat and nontoxic.