This specific 3D model, "Marquise Solitaire Ring 3D print model 3", is an asset made available by "Unknown author".
Can be downloaded at "Unknown platform" by following the link.
The license for this digital asset is "Unknown license".
STL (Stereolithography, filesize: 7.95 MB), 3DM (Rhinoceros 3D, filesize: 5.08 MB)