Periodic structures, such as photonic crystals and gratings, offer the ability to control light propagation and produce structural colors (not produced by pigments). Structural colors are quite widespread in nature, such as in opals and some animals. The abalone shells attract much attention due to its fracture resistant. In present work, we report on the microstructure of the surface area in where the iridescence color appears found in abalone shell shows a groove structure of blaze grating. The scanning electron microscopy (SEM) images of its iridescent layer show layers of platelets. The abalone shell has a statistically regular arranged tile structure. This specific tile structure serves as a two-dimensional grating to cause the iridescence phenomenon. Unlike opals, the iridescence color of the abalone shells is not directional due to the two-dimensional arrangement of the reflection grating structure and the convex shape of the tiles.