Pure iron has a hardness that ranges from 4 to 5. It is soft and ductile. Iron can be easily magnetized at ordinary temperatures and at 790?C the magnetic property disappears. Pure iron melts at about 1535?C, boils at 2750?C, and has a specific gravity of 7.86. Chemically, iron is an active metal. When exposed to humid air, iron forms a reddish-brown, flaky, decay known as rust.
Iron is the fourth most abundant element in the Earth?s crust. Because it is so common, iron has been used by human society for thousands of years. Iron was known and used for weapons in prehistoric ages, the earliest example still in existence; a group of rusty iron beads found in Egypt, dates from about 4000BC. This period in history was given the name Iron Age because it was the time when people found ways to get iron and to use it for building tools and weapons.
The beginnings of modern processing of iron can be traced back to central Europe in the mid-14th century BC. Pure iron has limited use in today?s world. Commercial iron always contains small amounts of carbon and other impurities that change its physical properties, which are much improved by the further addition of carbon and other alloying elements. This helps to prevent oxidation, also known as rust.
Iron is an essential part of a healthy diet. Iron compounds are employed for medicinal purposes in the treatment of anemia, when the amount of hemoglobin or the number of red blood corpuscles in the blood is lowered. Iron is a component of the complex compound in red blood cells called hemoglobin. This substance is responsible for carrying oxygen from your lungs to the rest of your body.