I design jewelry using polymer clay, it is waterproof and sturdy after it has been baked. I want to try this using a 3d printer that uses resin or very hard plastic, and most of the jewelry I make is black which I do sometimes add color for contrast using powdered watercolor paint with water or just some metallic powders and then cover it with a gloss. I want it to be very smooth.

i think resin would be your best bet but i have made some jewelry with my fdm machine.but would depend on size and shape of your model