Metallurgy

Let's analyze each option:Option A:Cuprite is a copper oxide (formula: $Cu _2 O$ ).Haematite is an iron oxide (formula: $Fe _2 O _3$ ).Both are oxide ores, so this match is correct.Option B:Calamine is a historical name used for zinc carbonate minerals like smithsonite (formula: $ZnCO _3$ ).Siderite is an iron carbonate (formula: $FeCO _3$ ).Both belong to the carbonate ore group, so this match is correct.Option C:Magnetite is an iron oxide (formula: $Fe _3 O _4$ ).The term "matachite" is questionable and "sticate ores" is not a standard classification.Magnetite belongs to oxide ores, not a supposed "sticate" category.Therefore, this match is incorrect.Option D:Sphalerite is a zinc sulphide (formula: ZnS )."Fool's gold" refers to pyrite, which is an iron sulphide (formula: $FeS _2$ ). Both are sulphide ores, making this match correct.Based on the above, the incorrectly matched set is in Option C.