Suppose all raindrops were small transparent cubes. Would this alter the looks of a rainbow? I mean would it still be visible at all, and if so, would it still have the same shape?
Or will all cubes just let light pass as if they were not present? I mean, all sides are flat, so the light waves are not dispersed after entering and exiting (the light is transmitted straight through the cubes or reflected as in a mirror).
If the cubes can't do the job of transforming the rainbow, are there (symmetric or non-symmetric) forms thinkable for the icecubes so that they give a different form than the normal rainbow? Symmetric (hexagon formed) ice crystals are already mentioned, but these are one-dimensional. The effects they produce include a wide variety of effects (see the links below). What kind of small transparent ice cubes can I throw from the sky to make a new kind of rainbow appear?
As @rob pointed out some real life examples are to be found here. The examples involve water droplets as well as ice crystals. @Ruslan gave a link to snow dogs, also an effect due to ice crystals in the atmosphere. There is already a great variety to be seen. To say the least. All effects are in a way similar to a circular rainbow (except the sun dogs). Will all collections of small and equal pieces of transparant ice (or, say, diamond dust blown into the air, if affordable) produce circular patterns? Will all these collections produce the same dispersion of colors as seen in a rainbow? It's a bit a running of of the mind question, but nevertheless... I'm really interested what would be seen if diamond dust were blown in the wind on a crisp an claer sunny day.