This ring started as a concept image of a twig wrapped into a band. Meshy, an AI 3D tool, turned the image into a mesh. In Blender the mesh was sized to US 7 and checked as a closed solid, which a model needs before it can be printed and cast.
The bark is shallow in the model, so most of its texture would come from finishing: a satin finish along the branch and a polish on the knots and the cut ends.