When the meteorite is formed it starts out as entirely molten taenite ( greater than 1500 ?C ) and as it cools past 723 ?C the primary metastable phase of the alloy changes into taenite and kamacite begins to precipitate out.
32.
A very high specific gravity becomes very pronounced in native metals; kamacite, an iron-nickel alloy common in iron meteorites has a specific gravity of 7.9, and gold has an observed specific gravity between 15 and 19.3.
33.
For kamacite, the alloy is usually in the proportion of 90 : 10 to 95 : 5, although impurities ( such as cobalt or carbon ) may be present, while for taenite the nickel content is between 20 % and 65 %.
34.
He took in hand an extensive but ill-organized collection of meteorites in the museum and from his study with electron probe work discovered the Agrell effect , the decrease in the nickel content of kamacite as a boundary with taenite is approached.
35.
Two examples are kamacite and taenite, which are found in iron meteorites; these species differ by the amount of Ni in the alloy; kamacite has less than 5 7 % nickel and is a variety of native iron, whereas the nickel content of taenite ranges from 7 37 %.
36.
Two examples are kamacite and taenite, which are found in iron meteorites; these species differ by the amount of Ni in the alloy; kamacite has less than 5 7 % nickel and is a variety of native iron, whereas the nickel content of taenite ranges from 7 37 %.
37.
The formation of Ni-poor kamacite proceeds by diffusion of Ni in the solid alloy at temperatures between 700 and 450 �C, and can only take place during very slow cooling, about 100 to 10, 000 �C / Myr, with total cooling times of 10 Myr or less.
38.
"' 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 micrometres wide.
39.
"' 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 micrometres wide.
40.
The researchers found that the fragments from the crater zone had a chondritic texture and the following mineral composition : pyroxene ( 1 ) 40 %, olivine 20 %, feldspar 10 %, pyroxene ( 2 ) 10 %; kamacite 15 %, troilite 5 %, and traces of chromite and native copper.
