Abalone's body is covered with a thick calcareous shell, and its shell is a right-handed spiral shell. The single-walled shell of abalone is hard and right-handed, and its surface is dark green and brown. The purple, green and white colors on the inside of the shell complement each other, just like gems.
In addition, there are a series of spiral protrusions on the shell of abalone, which gradually increase from the top of the shell to the ventral surface. Some of these protrusions penetrate into holes near the end of the spiral layer, and the number of holes varies with different types. There are 4-5 Haliotis discus hannai in northern China and 7-9 Haliotis diversicolor in southern China. China named abalone "nine-hole snail" in ancient times, which is derived from this feature.