A remixed version of the Pyrite-like Penholder by ncsandor (https://www.printables.com/model/55654-pyrite-like-penholder) which can successfully be printed in vase mode.
The outer surface was isolated and solidified, manifold errors fixed, and flat horizontal surfaces tilted to avoid large gaps appearing when the contour was spiralized in Cura. The resulting print is not watertight but looks good and prints successfully at avg layer heights.
Wide line widths and thin layers are recommended for best results with no large gaps. I got good results on a 0.4mm nozzle by turning extrusion width up to 0.7mm, layer height to 0.16mm, and flow to 110%
The author remixed this model.