geometric ring 3d model

A ring based on a regular pentagonal antiprism (middle belt of an icosahedron), perfectly 5-fold rotational symmetry (C5v), 10 alternating equilateral triangle facets around the outer perimeter (5 pointing up, 5 pointing down), regular pentagon top and bottom flat rims, perfectly circular cylinder hole in the center. Pure hard-surface geometry, sharp chamfered edges, planar flat facets, architectural jewelry, metallic titanium finish, mathematically precise.