Jewellers rouge, also known as red rouge or red jewellers rouge, is a type of polishing compound commonly used in jewelry making and metalworking. It is an abrasive powder that is applied to a polishing wheel or cloth to give a high polish to metals such as gold, silver, and brass.

Option 1: Ferric oxide is the correct answer. Ferric oxide, also known as iron(III) oxide, is a compound made up of iron and oxygen. It is commonly used as a pigment in paints, but it is also highly effective as a polishing agent due to its abrasive properties. When applied to a polishing wheel or cloth, ferric oxide particles help to remove surface imperfections and scratches, resulting in a smooth and shiny finish.

Option 2: Ferrous oxide, also known as iron(II) oxide, is a different compound from ferric oxide. It is less commonly used as a polishing agent and does not have the same abrasive properties.

Option 3: Ferrous carbonate is a compound made up of iron, carbon, and oxygen. It is not commonly used as a polishing agent and does not have the same properties as jewellers rouge.

Option 4: Ferric carbonate is another compound made up of iron, carbon, and oxygen