Final answer:
Hematite has the formula Fe2O3, while limonite is a mixture of hydrated iron oxides with the general formula FeO(OH)·nH2O, where 'n' can vary.
Step-by-step explanation:
The minerals hematite and limonite are iron oxides with distinctive major colors and properties. Hematite has the chemical formula Fe2O3, which corresponds to an iron to oxygen ratio of 2:3. This formula can be derived from the empirical formula determination based on mass percentages of iron and oxygen in a sample.
Limonite, on the other hand, is not a single mineral but a mixture of similar hydrated iron oxide minerals. Its general formula is often written as FeO(OH)·nH2O, indicating the presence of iron, oxygen, and variable amounts of water. As a result, limonite can have a range of compositions and is normally identified by its physical characteristics and ochre hues.