Jewelers rouge is an abrasive powder used for a final polish on glass and soft metals like gold and silver. The powder is made up of fine, very pure red iron oxide.
The rouge can be applied as a dry powder or as a thick paste. The material used to make the rouge burnishes the surface it is applied to rather than cut into it like some alumina abrasives can do. When the material is used on gold, it actually tints the gold, which slightly changes the final appearance of the pieces. The rouge can be bought as a powder, a paste or even mixed in with a wax or grease binder and placed into a bar form.