Rings » Unidentified Onyx Marcasite Ring Unidentified Onyx Marcasite Ring Unidentified Onyx Marcasite Ring. Signed "925" on one side and "SC" on the other side. Unidentified Onyx Marcasite Ring. Signed "925" on one side and "SC" on the other side. Unidentified Onyx Marcasite Ring. Signed "925" on one side and "SC" on the other side. Unidentified Onyx Marcasite Ring. Signed "925" on one side and "SC" on the other side. Unidentified Onyx Marcasite Ring. Signed "925" on one side and "SC" on the other side. Unidentified Onyx Marcasite Ring. Signed "925" on one side and "SC" on the other side. 2022-07-30