Printed with Winkle's Marble filament with a 0.6 nozzle for speed and it looks quite good. If printed with a 0.4 one you'll definitely get a better quality.
I used support (only touching the build-plate) on the base piece, as the overhangs are a bit extreme. I believe you may not need them if you use a 0.4mm noozle.
The author hasn't provided the model origin yet.