At present, azurol mud, which is generally recognized in the industry, is a kind of raw ore soil and molding agent, and its appearance and color are blue-purple mud minerals. This mineral is produced between black mud and purple mud in the purple mud seam of Huanglong Mountain, close to black mud, with gray appearance and hard texture, which is very similar to celadon gypsum and lacks the purple color that celadon gypsum should have.

Azure mud in history, according to ancient records, is mainly produced in Huanglongshan mining area of Dingshu Town. "Yangxian Tea Pot System" says that "green mud makes pear trees" (the old new trees are part of Huanglongshan mining area). It is said that the Dashuitan in Dingshan was originally the gateway for mining purple sand mud, producing azure mud.