I printed a 6 sided die from Thingiverse and then sanded it with 200, 400, 800, 1000 and 3000 grit paper and this was the result. I’m pretty darned impressed with that. When you wet the die, it looks even better than it does here (dry). The picture was taken with a macro lens on a DSLR, but I had to shrink it to 25% size to upload here. The die is 15mm.
I know people have made lenses with clear resin, but for this application, that level of dedication wasn’t necessary.