It is a ferrous metal.
According iron content it can be divided into-
Magnetite (Fe3 04): (Iron content up to 72.4%). It is a black mineral formed in igneous or metamorphic rocks in veins or lodes. It has excellent magnetic qualities.
Uses: Magnetite iron is used as natural magnets and in electrical industry.
Haematite (Fe2 O3): (Iron content 70%) Most important iron ore. They are red ores derived from sedimentary rocks and occur in crystalline or in powdery forms.
Haematite iron is most important for the purpose of industrial use.
Limonite (2Fe2 03 H20): (Iron content 60%) This is brown ore occurring in thick beds in sedimentary rock sequence or in swamps or lakes. (Lake or bog iron).
Siderite (Fe Co3): (Iron content up to 48%) This is ash-grey in colour and is found interbedded with other sedimentary rocks.
Uses: It is basically used for making steel.
Nature: It is a hard, silvery metal with a bluish tinge and a metallic lustre.
i. Increases the hardenability of steel if mixed alongwith nickel.
ii. It is used for making stainless steel which is widely used in manufacture of machinery where steam, water, moist air or acids would corrode ordinary steels quickly.
iii. Larger amounts, 12-15% increase high temperature strength and corrosion resistance, as well as resistance to wear. Therefore, kitchen utensils, cutlery, oil burner components and bearings are made.
iv. Chromite ore is also used as a refractory material in basic brick linings of various metallurgical furnaces-chromite or chrome magnesite brick.
v. Chromium, used in making nickel-chromium alloys (nichrome), is highly resistant to electric current and is thus used as a safety measure in electric wires, toasters and other electrical appliances.
vi Chromium salts and compounds (chromates) are used in the manufacture of paint pigments, chemical industry, for leather tanning, metal and wood to prevent rotting.