As the light from the star passes though the ring material, then the longest wavelength will be scattered first
maybe debris of different elements ( different density ) and thus different colours is forming rings of different radii?
maybe not with a monochromatic light source.
Rings of tiny little drops of water/liquid forming rainbows in space
Nice image. Not realistic. The vapour pressure of water warm enough to be liquid means it would evaporate in seconds. (There is a shudder-making story of a 1960s NASA technician who was exposed to vacuum in an accident while testing space suits in some way. He reported feeling the tears boiling from the surface of his eyes. Now there's a line for the "death cries" OXP !)
Ice bows, on the other pseudopod ... there's an idea. "Sun dogs
Different colours of rock - well, it does happen, but it's a pretty subtle effect. The division of asteroids into compositional families relies on such differences, but didn't really get started until improvements in spectroscope technology in the late 1950s/ early 1960s. For the first decade of it's existence, the 200in Mt Palomar "light bucket" couldn't gather enough light to tell the difference in a night's observing.
Isn't there an OXP for an attachment to your ship's comms laser that can tell you the composition of an asteroid? See, even in the Ooniverse, the colours (reflection and/ or fluorescence spectroscopy) of asteroids, splinters and boulders are so subtle that you need some fancy kit to detect it.
On the third pseudopod, there are fair grounds for having a radial variation in grain size in a planet's rings. That's the main reason for the difference in reflection and scattering brightness of Saturn's rings. (IIRC)
Arrgh! I must extrude another pseudopod, then cut it off. The first light from a spectrum to be scattered by (colour neutral) particles is the SHORTEST wavelength (hence Earth's blue skies), not the longest.
Anyone for barbecued pseudopod? Fresh! Still seeping ichor.