Which of the following is NOT an ore of iron?

The correct answer is option 1. Cuprite.

Cuprite \((Cu_2O)\) is a mineral consisting of copper(I) oxide, not iron. It is a source of copper rather than iron.

The other options listed are indeed ores of iron:

2. Haematite \((Fe_2O_3)\) is an important iron ore and a primary source of iron.

3. Magnetite \((Fe_3O_4)\) is another significant iron ore, known for its magnetic properties.

4. Siderite \((FeCO_3)\) is also an iron ore, although it is less commonly mined compared to haematite and magnetite.