The following are ores of metals EXCEPT

Analyze the question: We need the substance that is NOT an ore of a metal.

Concept: An ore is a naturally occurring mineral from which a metal can be extracted profitably.

Checking each option:

• A. Bauxite: Al₂O₃·2H₂O, the ore of aluminium. It is a metal ore.
• B. Dolomite: CaCO₃·MgCO₃, a source of magnesium (and calcium). It is a metal ore.
• C. Graphite: a form (allotrope) of carbon, which is a non-metal. It is not an ore of any metal.
• D. Haematite: Fe₂O₃, the ore of iron. It is a metal ore.
• E. Magnetite: Fe₃O₄, another ore of iron. It is a metal ore.

Answer: Graphite is the only option that is not a metal ore, so the correct option is C.

Tip: Remember common ores in pairs:

• Bauxite → Aluminium
• Haematite and Magnetite → Iron
• Galena → Lead
• Cassiterite → Tin
• Dolomite → Magnesium/Calcium

Graphite, diamond and coal are all forms of carbon (a non-metal), so if you see them in an "ore" question, they are usually the odd one out.