Mineralogy of Iron

Next to aluminium, iron is the most abundant and widely distributed metal in the crust of the earth and Mineralogy of Iron is very important part of the industry. It is seldom found free in nature owing to the extreme readiness with which it combines with moist air to form the hydrated oxide known as rust. Such ferruginous minerals as contain a sufficiently high percentage of iron, possess a suitable chemical composition, and occur in nature in large quantity, are termed ores and are used for the commercial extraction of iron. Owing to their economic importance the ores of iron have been studied with unusual care, and the suitability of the more important types for metallurgical purposes is discussed in Part III. of this volume.

Mineralogy of Iron discovers the various minerals containing iron and it may be conveniently to classify them according to the state of the chemical combination of the iron, and the system adopted here is schematically represented as follows: -

1. Native Iron.
2. Oxides: Magnetites, Fe₃O₄; Haematites: Red, anhydrous ores, Fe₂O₃; Red-brown, hydrated ores, Fe₂O₃.xH₂O.
3. Carbonates - spathic ores, FeCO₃.
4. Sulphides - pyrites.
5. Miscellaneous Minerals.