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Meteoric iron forms a few different structures that can be seen by etching or in thin sections of meteorites. The Widmanstätten pattern forms when meteoric iron cools and kamacite is exsolved from taenite in the form of lamellas. [5] Plessite is a more fine-grained intergrowth of the two minerals in between the lamella of the Widmanstätten ...
Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric iron. [1] Stony-iron meteorites are all differentiated, meaning that they show signs of alteration.
Iron meteorites, also called 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 iron meteorites originate from cores of planetesimals, [3] with the exception of the IIE iron meteorite group. [4]
The 60-tonne, 2.7 m-long (8.9 ft) Hoba meteorite in Namibia is the largest known intact meteorite.[1]A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon.
However, the appearance, the composition, and the formation process of these terrestrial Widmanstätten structures are different from the characteristic structure of iron meteorites. [19] When an iron meteorite is forged into a tool or weapon, the Widmanstätten patterns remain but become stretched and distorted.
The Sikhote-Alin meteorite is the heaviest of these and was an observed fall, [7] while the Old Woman meteorite is, at 38 × 34 × 30 inches (970 × 860 × 760 mm) and 6,070 pounds (2,750 kg) originally, the largest meteorite found in California and the second largest found in the United States.
The silicate inclusions are composed of low-Ca pyroxene, high-Ca pyroxene, olivine, plagioclase, troilite, graphite, different phosphates, meteoric iron and traces of daubréelite and chromite. [2] This composition is very similar to the composition of winonaites , and it is therefore argued that the two groups share the same parent body.
Pallasites are a rare type of meteorite. Only 61 are known to date, including 10 from Antarctica, with four being observed falls. [9] [10] The following four falls are in chronological order: Mineo, Sicily, Italy. A luminous meteor was observed and an object seen to fall with a loud roar in May 1826. Only 46 grams (1.6 oz) are preserved in ...