Seven colors refer to the colors separated by different wavelengths after sunlight is refracted by a prism.

Seven colors were first seen in Colorful Xiangyun, which is actually a natural phenomenon caused by the sun's rays and the structure of ice crystals in the clouds. Under the right weather conditions, sunlight forms a right angle with the clouds. When sunlight passes through the clouds, the water vapor in the clouds above separates the solar spectrum through refraction and reflection, thus scattering seven colors of light.