Meteoric iron, sometimes meteoritic iron, is a

native metal A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include aluminium, antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, m ...

and early-universe protoplanetary-disk remnant found in

meteorites A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object ...

and made from the elements

iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in ...

and

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow t ...

, mainly in the form of the

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

phases kamacite and

taenite Taenite is a mineral found naturally on Earth mostly in iron meteorites. It is an alloy of iron and nickel, with a chemical formula of and nickel proportions of 20% up to 65%. The name is derived from the Greek ταινία for "band, ribbon" ...

. Meteoric iron makes up the bulk of

iron meteorite Iron meteorites, also known as siderites, or ferrous meteorites, are a type of meteorite that consist overwhelmingly of an iron–nickel alloy known as meteoric iron that usually consists of two mineral phases: kamacite and taenite. Most i ...

s but is also found in other meteorites. Apart from minor amounts of

telluric iron Telluric iron, also called native iron, is iron that originated on Earth, and is found in a metallic form rather than as an ore. Telluric iron is extremely rare, with only one known major deposit in the world, located in Greenland. Introduction W ...

, meteoric iron is the only naturally occurring native metal of the element iron (in metallic form rather than in an

ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 Apr ...

) on the Earth's surface.

Mineralogy

The bulk of meteoric iron consists of

and kamacite. Taenite is a face-centered cubic and kamacite a body-centered cubic iron-nickel

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductili ...

. Meteoric iron can be distinguished from

by its microstructure and perhaps by its chemical composition also, since meteoritic iron contains more nickel and less carbon. Trace amounts of

gallium Gallium is a chemical element with the Symbol (chemistry), symbol Ga and atomic number 31. Discovered by France, French chemist Paul-Émile Lecoq de Boisbaudran in 1875, Gallium is in boron group, group 13 of the periodic table and is similar to ...

and

germanium Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid in the carbon group that is chemically similar to its group neighbors ...

in meteoric iron can be used to distinguish different meteorite types. The meteoric iron in stony iron meteorites is identical to the "gallium-germanium group" of the

Structures

Meteoric iron forms a few different structures that can be seen by

etching Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal. In modern manufacturing, other chemicals may be used on other types ...

or in

thin section In optical mineralogy and petrography, a thin section (or petrographic thin section) is a thin slice of a rock or mineral sample, prepared in a laboratory, for use with a polarizing petrographic microscope, electron microscope and electron ...

s of meteorites. The

Widmanstätten pattern Widmanstätten patterns, also known as Thomson structures, are figures of long nickel–iron crystals, found in the octahedrite iron meteorites and some pallasites. They consist of a fine interleaving of kamacite and taenite bands or ribbons ...

forms when meteoric iron cools and kamacite is exsolved from

in the form of lamellas.

Plessite Plessite is a meteorite texture consisting of a fine-grained mixture of the minerals kamacite and taenite found in the octahedrite iron meteorites. It occurs in gaps (its name is derived from the Greek "plythos" meaning "filling"according tMinda ...

is a more fine-grained intergrowth of the two minerals in between the lamella of the Widmanstätten pattern.

Neumann lines Neumann lines, or Neumann bands, are fine patterns of parallel lines seen in cross-sections of many hexahedrite iron meteorites in the kamacite phase, although they may appear also in octahedrites provided the kamacite phase is about 30 micrometr ...

are fine lines running through kamacite crystals that form through impact-related deformation.

Cultural and historical usage

Before the advent of iron

smelting Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a c ...

, meteoric iron was the only source of iron metal apart from minor amounts of

. Meteoric iron was already used before the beginning of the

Iron Age The Iron Age is the final epoch of the three-age division of the prehistory and protohistory of humanity. It was preceded by the Stone Age ( Paleolithic, Mesolithic, Neolithic) and the Bronze Age ( Chalcolithic). The concept has been mostly ...

to make cultural objects, tools and weapons.Waldbaum, J. C. and James D. Muhly; ''The first archaeological appearance of iron and the transition to the iron age'' chapter in ''The coming of the age of iron,'' Theodore A. Wertme. ed., Yale University Press, 1980,

Bronze Age

Many examples of iron working from the

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second pri ...

have been confirmed to be meteoritic in origin. *In ancient Egypt an iron metal bead was found in a graveyard near Gerzeh that contained 7.5% Ni. Dated to around 3200 BC,

geochemical Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...

analysis of the Gerzeh iron beads, based on the ratio of nickel to iron and

cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...

, confirms that the iron was meteoritic in origin. *Dated to around 2500 BC, an iron dagger from

Alaca Höyük Alacahöyük or Alaca Höyük (sometimes also spelled as ''Alacahüyük'', ''Euyuk'', or ''Evuk'') is the site of a Neolithic and Hittite settlement and is an important archaeological site. It is situated in Alaca, Çorum Province, Turkey, nor ...

was confirmed to be meteoritic in origin through geochemical analysis. *Dated to around 2300 BC, an iron pendant from

Umm el-Marra Umm el-Marra, ( ar, أم المرى), east of modern Aleppo in the Jabbul Plain of northern Syria, was one of the ancient Near East's oldest cities, located on a crossroads of two trade routes northwest of Ebla, in a landscape that was much more f ...

in Syria was confirmed to be meteoritic in origin through geochemical analysis. *Dated to around 1400 BC, an iron axe from

Ugarit ) , image =Ugarit Corbel.jpg , image_size=300 , alt = , caption = Entrance to the Royal Palace of Ugarit , map_type = Near East#Syria , map_alt = , map_size = 300 , relief=yes , location = Latakia Governorate, Syria , region = ...

in Syria was found to be meteoritic in origin. *Dated to around 1400 BC, several iron axes from the

Shang Dynasty The Shang dynasty (), also known as the Yin dynasty (), was a Chinese royal dynasty founded by Tang of Shang (Cheng Tang) that ruled in the Yellow River valley in the second millennium BC, traditionally succeeding the Xia dynasty a ...

in China were also confirmed to be meteoritic in origin. *Dated to around 1350 BC, an iron dagger, bracelet and headrest from the tomb of

Tutankhamun Tutankhamun (, egy, twt-ꜥnḫ-jmn), Egyptological pronunciation Tutankhamen () (), sometimes referred to as King Tut, was an Egyptian pharaoh who was the last of his royal family to rule during the end of the Eighteenth Dynasty (ruled ...

were confirmed to be meteoritic in origin. The Tutankhamun dagger consists of similar proportions of metals (

and

) to a meteorite discovered in the area, deposited by an ancient meteor shower.

The Americas

*The

Inuit Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally similar indigenous peoples inhabiting the Arctic and subarctic regions of Greenland, Labrador, Quebec, Nunavut, the Northwest Territorie ...

used parts of the

Cape York meteorite The Cape York meteorite, also known as the Innaanganeq meteorite, is one of the largest known iron meteorites, classified as a medium octahedrite in chemical group IIIAB. In addition to many small fragments, at least eight large fragments with a ...

to make lance heads.

Africa

*Fragments from the Gibeon meteorite were used for centuries by the

Nama people Nama (in older sources also called Namaqua) are an African ethnic group of South Africa, Namibia and Botswana. They traditionally speak the Nama language of the Khoe-Kwadi language family, although many Nama also speak Afrikaans. The Nama Pe ...

of Namibia.

Asia

*There are reports of the use of meteorites for manufacture of various items in Tibet (see

Thokcha ''Thokcha'' (; also alternatively ) are tektites and meteorites which serve as amulets. Typically high in iron content, these are traditionally believed to contain a magical, protective power comparable to Tibetan dzi beads. Most ''thokcha'' a ...

). *The ''Iron Man'', a purported Tibetan Buddhist statue of

Vaiśravaṇa (Sanskrit: वैश्रवण) or (Pali; , , ja, 毘沙門天, Bishamonten, ko, 비사문천, Bisamuncheon, vi, Đa Văn Thiên Vương), is one of the Four Heavenly Kings, and is considered an important figure in Buddhism. Names The n ...

, was likely carved from an ataxite meteorite.Der Lama mit der Hose: „Buddha from space“ ist offenbar eine Fälschung (Telepolis 13.10.2012)
/ref> It has been speculated that it may be made from a fragment of the

Chinga meteorite The Chinga meteorite is an iron meteorite. It is structurally an ataxite with very rare kamacite lamella. The meteoric iron is a part of the lamella taenite. The total chemical composition is 82.8% iron, 16.6% nickel, and the rest mostly cobalt and ...

. Even after the invention of

, meteoric iron was sometimes used where this technology was not available or metal was scarce. A piece of the

Cranbourne meteorite The Cranbourne meteorite is an octahedrite iron meteorite. It is the second largest meteorite found in Australia after the Mundrabilla meteorite, but at the time of discovery it was the largest known iron meteorite in the world. It is classifie ...

was made into a horseshoe around 1854. Today meteoritic iron is used in niche jewellery and knife production, but most of it is used for research, educational or

collecting The hobby of collecting includes seeking, locating, acquiring, organizing, cataloging, displaying, storing, and maintaining items that are of interest to an individual ''collector''. Collections differ in a wide variety of respects, most obvi ...

purposes.

Atmospheric phenomena

Meteoric iron also has an effect on the Earth's atmosphere. When meteorites descend through the atmosphere, outer parts are

ablated Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for ...

. Meteoric ablation is the source of many elements in the upper atmosphere. When meteoric iron is ablated, it forms a free iron atom that can react with

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the l ...

(O₃) to form FeO. This FeO may be the source of the orange spectrographic bands in the spectrum of the upper atmosphere.

References

External links

Pictures of the iron beads of Gerzeh and other artifacts from tomb number 67
{{Meteorites Iron Meteorite minerals Native element minerals