It is actually produced by a chemical reaction: the main chemical component of protein is a kind of protein. When eggs are kept for a long time, some protein in protein will break down into amino acids. The chemical structure of amino acid has a basic amino group and an acidic carboxyl group, so it can interact with acidic and alkaline substances. Therefore, when people design preserved eggs, they deliberately put some alkaline substances in the mud, such as lime, potassium carbonate and sodium carbonate. They will pass through the holes in the eggshell and combine with amino acids to form amino acid salts. These amino acid salts are insoluble in protein, so they crystallize in a certain geometric shape to form beautiful pine flowers.

The loose pattern in preserved eggs is hydrated crystals of magnesium hydroxide. During the curing process of duck eggs, alkaline components infiltrated into the eggs through the pores of the eggshell, which led to the gradual alkali solidification of egg white protein and the formation of hydrated crystals of magnesium hydroxide in the process. This kind of crystal is arranged along a certain gap in the egg white gel, and the number is gradually increasing, so that pine-like crystals appear; At the same time, under the action of alkalinity, protein in egg white degrades a small amount of amino acids. When amino acids meet metal substances, they will generate metal salts, which are distributed in the gaps of egg white gel. With the increase of the number, they will also form patterns similar to pine trees.