Meteoric iron
| Meteoric iron (native iron) | |
|---|---|
 Widmanstätten pattern on a 500g endcut from the Toluca iron meteorite | |
| General | |
| Category | Native element mineral |
| Formula (repeating unit) | Fe and Ni in different ratios |
| Space group | Different structures |
| Identification | |
| Luster | Metallic |
| Diaphaneity | Opaque |
Meteoric iron, sometimes meteoritic iron,
Mineralogy
The bulk of meteoric iron consists of taenite and kamacite. Taenite is a face-centered cubic and kamacite a body-centered cubic iron-nickel alloy.
Meteoric iron can be distinguished from telluric iron by its microstructure and perhaps by its chemical composition also, since meteoritic iron contains more nickel and less carbon.[2]
Trace amounts of
| Mineral | Formula | Nickel (Mass-% Ni) | Crystal structure | Notes & references |
|---|---|---|---|---|
| Antitaenite | γLow Spin-(Ni,Fe) | 20–40 | face centered cubic | Only approved as a variety of taenite by the IMA |
| Kamacite | α-(Fe,Ni); Fe0+0.9Ni0.1 | 5–10 | body centered cubic | Same structure as ferrite |
| Taenite | γ-(Ni,Fe) | 20–65 | face centered cubic | Same structure as austenite |
| Tetrataenite | (FeNi) | 48–57 | tetragonal | [4] |
Structures
Meteoric iron forms a few different structures that can be seen by
Cultural and historical usage
Before the advent of iron smelting, meteoric iron was the only source of iron metal apart from minor amounts of telluric iron. Meteoric iron was already used before the beginning of the Iron Age to make cultural objects, tools and weapons.[8]
Bronze Age
| Iron in hieroglyphs | ||||||
|---|---|---|---|---|---|---|
bjꜣ-n-p.t literally "metal of the sky" | ||||||
Many examples of iron working from the Bronze Age have been confirmed to be meteoritic in origin.[9]
- In ancient Egypt an iron metal bead was found in a graveyard near Gerzeh that contained 7.5% Ni.[10][11] Dated to around 3200 BC, geochemical analysis of the Gerzeh iron beads, based on the ratio of nickel to iron and cobalt, confirms that the iron was meteoritic in origin.[9]
- Dated to around 2500 BC, an iron dagger from Alaca Höyük was confirmed to be meteoritic in origin through geochemical analysis.[9]
- Dated to around 2300 BC, an iron pendant from Umm el-Marra in Syria was confirmed to be meteoritic in origin through geochemical analysis.[9]
- Dated to around 1400 BC, an iron axe from Ugarit in Syria was found to be meteoritic in origin.[9]
- Dated to around 1400 BC, several iron axes from the Shang Dynasty in China were also confirmed to be meteoritic in origin.[9]
- Dated to around 1350 BC, an iron dagger, bracelet and headrest from the tomb of
- Dated to around 900 BC, an iron arrowhead from Mörigen in Switzerland was confirmed to be meteoritic in origin.[15]
The Americas
- The Inuit used parts of the Cape York meteorite to make lance heads.[16][17][18]
Africa
- Fragments from the Gibeon meteorite were used for centuries by the Nama people of Namibia.
Asia
- There are reports of the use of meteorites for manufacture of various items in Tibet (see Thokcha).
- The Iron Man, a purported Tibetan Buddhist statue of Vaiśravaṇa, was likely carved from an ataxite meteorite.[19] It has been speculated that it may be made from a fragment of the Chinga meteorite.[20][21]
Even after the invention of smelting, meteoric iron was sometimes used where this technology was not available or metal was scarce. A piece of the Cranbourne meteorite was made into a horseshoe around 1854.[22]
Today meteoritic iron is used in niche jewellery and knife production, but most of it is used for research, educational or collecting purposes.
Atmospheric phenomena
Meteoric iron also has an effect on the Earth's atmosphere. When meteorites descend through the atmosphere, outer parts are ablated. 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 (O3) to form FeO. This FeO may be the source of the orange spectrographic bands in the spectrum of the upper atmosphere.[23]
See also
References
- .
- ^ ISBN 978-0-924171-95-6.
- .
- Bibcode:1980AmMin..65..624C.
- .
- .
- .
- ISBN 978-0300024258
- ^ ISSN 0305-4403.
- ^ "Pre-Dynastic Iron Beads from Gerzeh, Egypt". ucl.ac.uk. Archived from the original on 7 April 2015. Retrieved 28 December 2012.
- hdl:11568/908268.
- .
- .
- ^ Walsh, Declan (2 June 2016). "King Tut's Dagger Made of 'Iron From the Sky,' Researchers Say". The New York Times. Retrieved 4 June 2016.
...the blade's composition of iron, nickel and cobalt was an approximate match for a meteorite that landed in northern Egypt. The result "strongly suggests an extraterrestrial origin"
- ^ Guy, Jack (8 August 2023). "Arrowhead made from meteorite 3,000 years ago found near lake in Europe". CNN. Retrieved 9 August 2023.
- ^ Iron and steel in ancient times by Vagn Fabritius Buchwald - Det Kongelige Danske Videnskabernes Selskab 2005
- JSTOR 2844401.
- JSTOR 2844401.
- ^ Der Lama mit der Hose: „Buddha from space“ ist offenbar eine Fälschung (Telepolis 13.10.2012)
- ^ "Ancient Buddhist Statue Made of Meteorite, New Study Reveals". Science Daily. Retrieved 26 December 2012.
- .
- ^ "The Cranbourne Meteorites" (PDF). City of Casey. Archived from the original (PDF) on 10 May 2013. Retrieved 29 December 2012.
- S2CID 130887275.
External links
