A phenomenon seen as a flash of sunlight shineing down a lunar valley during a total solar eclipse: A diamond-ring effect is created as the total phase of a solar eclipse is about to begin, when the last Baily's bead, a remaining bit of phosphere, glows so intensely by contrast with the Sun's faint corona that it looks like the jewel on a ring.

The diamond-ring effect also refers to the equivalent phase at the end of totality.