This is a display stand for a glass marble. It is stable and has a spherical cutout for a 1.5 inch (38mm) marble, but can be scaled as appropriate for larger or even smaller marbles.
It also has a small cutout feature on the base that can be used to string in wires for LED up-lighting.
I printed out of PETG, but just about any filament-- including flexible-- could be appropriate.
marble_holder.stl | 40.4KB |