Five percent of Earth’s crust is made up of iron. Native iron is rare in the crust and is invariably alloyed with nickel. Low-nickel iron (up to 7.5 percent nickel) is called kamacite, and high-nickel iron (up to 50 percent nickel) is called taenite. Both crystallize in the cubic system. A third form of iron-nickel, mainly found in meteorites and crystallizing in the tetragonal system, is called tetrataenite. All three forms are generally found either as disseminated grains or as rounded masses. Kamacite is the major component of most iron meteorites. It is found in most chondritic meteorites, and occurs as microscopic grains in some lunar rocks. Taenite and tetrataenite are mainly found in meteorites, often intergrown with kamacite. It is also plentiful in the Sun and other stars.

Name: An Old English word for the metal; the chemical symbol from the Latin ferrum.

Association: Pyrite, magnetite, troilite, w¨ustite, cohenite


Chemical Properties of Iron

Chemical Classification Native
Chemical Composition Fe

Physical Properties of Iron

Color Iron-black
Streak Grey
Luster Metallic
Cleavage Imperfect/Fair On {001}
Diaphaneity Opaque
Mohs Hardness 4½ on Mohs scale
Diagnostic Properties Specific gravity, color
Crystal System Cubic
Tenacity Malleable
Fracture Hackly
Density 7.3 – 7.87 g/cm3 (Measured)    7.874 g/cm3 (Calculated)
Parting On (112)

Optical Properties of Iron

Type Isometric
Colour in reflected light: White
Twinning (111), in lamellar masses also {112}.


Rare in igneous rocks, especially basalts; in carbonaceous sediments; in volcanic fumaroles; and in petrified wood, mixed with “limonite” and organic matter.

Uses Area

Near the producer of iron produced in the world is used in steel making. Because It alone is the successful strong depot.

Tungsten, manganese, nickel, vanadium, chrome etc. It is used in many areas such as construction and automobile.

Powder iron: used in metallurgy products, magnets, high frequency nuclei, automobile parts, catalysts.

The stainless steel is very resistant to corrosion. It contains at least 10.5% chromium. Other metals such as nickel, molybdenum, titanium and copper are added to increase the strength and workability. It is used in architecture, beds, cutlery, surgical instruments and jewelry.

Cast iron contains 3-5% carbon. It is used for pipes, valves and pumps. It’s not as hard as steel, but it’s cheap. Magnets can be made of ıts and its alloys and compounds.

It catalysts to produce ammonia in news processing and to convert syngas (hydrogen and carbon monoxide) into liquid fuels in Fischer-Tropsch process.

Radioactive iron (59): tracer in medicine, biochemical and metallurgical studies. Iron blue: paints, printing inks, plastics, cosmetics (eye shadow), painter colors, laundry blue, paper paint, fertilizer component, baked enamel coatings for automobiles and household appliances, industrial surfaces. Black iron oxide: as pigment, in polishing compounds, in metallurgy, in medicine, in magnetic inks, in ferrite for the electronics industry.

Biological Factor of Iron

It is an important element for all life forms and is not toxic. The average person contains about 4 grams of iron. Most of them in hemoglobin, in the blood. Hemoglobin carries oxygen from our lungs to the cells needed for tissue respiration.

People need 10 to 18 milligrams of iron every day. Iron deficiency causes anemia. Foods such as liver, kidney, molasses, brewer’s yeast, cocoa and licorice contain a lot of iron.

Iron Facts

  • Atomic number (number of protons in the nucleus): 26
  • Atomic symbol (Periodic Table of the Elements): Fe
  • Atomic weight (average mass of atom): 55.845
  • Density: 7.874 grams per cubic centimeter
  • Phase at room temperature: Solid
  • Melting point: 2,800.4 degrees Fahrenheit (1,538 degrees Celsius)
  • Boiling point: 5,181,8 F (2,861 C)
  • Isotope number (different number of neutrons containing the same element): (including how many stable isotopes): 33 Stable isotopes: 4
  • The most common isotopes: Iron-56 (natural abundance: 91.754 percent)


  • In Greenland, at Fortune Bay, Mellemfjord, Asuk, and elsewhere on the west coast; on Disko Island, near Uivfaq and Kitdlit.
  • From Ben Bhreck, Scotland.
  • At B¨uhl, near Weimar, Hesse, Germany. In Poland, near Rouno, Wolyn district.
  • In Russia, at Grushersk, in the Don district; from the Hatanga region, Siberia; in the Huntukungskii massif, Krasnoyarsk Kray; and on the Tolbachik fissure volcano, Kamchatka Peninsula.
  • In the USA, at Cameron, Clinton Co., Missouri; and near New Brunswick, Somerset Co., New Jersey.
  • In Canada, in Ontario, from Cameron Township, Nipissing district, and on St. Joseph Island, Lake Huron. Noted in small amounts at a number of additional localities.