In the mornings or evenings full of clouds and mist, standing on the high peaks, and viewing in the same direction as the light, tourists may see a colorful halo with blue color inside and red color outside present on the dimly discernible mist veil. In the middle of the halo, a human figure is reflected, and it looks just like the colorful halo over the head of the Buddha, so it is called "the Buddhist Light" or "the Treasure Light". The Buddhist Light of Taishan Mountain is a kind of natural phenomenon of optical diffraction, which mostly appears under the conditions of a half sunny and half misty day during the period from June to August, and at the time when the sun shines slantingly.