This specific 3D model, "Solitaire Engagement Art Deco Ring 3D print model 63", is an asset made available by "Unknown author".
Can be downloaded at "Unknown platform" by following the link.
This specific 3D model is provided under the "Unknown license" framework.
STL (Stereolithography, filesize: 11.6 MB), 3DM (Rhinoceros 3D, filesize: 19.7 MB)