Those analyses have revealed traces of gold and iron, along with rarer minerals such as kamacite, schreibersite, taenite
, and troilite.
Traces of rare minerals have also been found, including taenite
, troilite, kamacite and schreibersite.
Neutron tomographic imaging on Dingo and the ICON beamline in Switzerland assisted the investigators in discerning between the nickel-rich (taenite) and nickel-poor (kamacite) metallic phases of the meteorite.
Kamacite and taenite are cubic minerals in which the regular internal stacking of iron and nickel atoms follows the direction of the cube with planes of atoms intersecting at right angles.
Occurrence: In "plessite," an intergrowth of taenite
and kamacite; other associated minerals are: nickelphosphide, schreibersite, awaruite and graphite.
Main iron-nickel minerals are kamacite and taenite. Minor minerals include schreibersite, rhabdite, troilite, cohenite, graphite, and sphalerite (Buchwald 1975; Dominik 1976).
Selected microprobe analysis of the Morasko meteorite and micrometeorites (in per cent) Meteorite Kamacite Taenite O Si S 0.02 0.01 Fe 95.42 80.49 Ni 6.49 18.08 Mg Al Mn Total 101.1 98.6 [Fe.sub.3][0.sub.4] Fe00H Micrometeorites with low Ni content Sample 3/11 Sample PS/40 O 1.35 0.005 Si 1.18 0.004 S 0.01 0.001 Fe 55.93 62.97 Ni 0.001 0.001 Mg Al Mn Total 58.47 * 62.98 * [Fe.sub.3][0.sub.4] 77.2 86.9 Fe00H 88.9 100.1 Micrometeorite with high Ni content Sample 4/KKH O 6.77 Si 0.64 S Fe 87.04 Ni 4.66 Mg 0.05 Al 0.57 Mn 0.27 Total 100.0 [Fe.sub.3][0.sub.4] Fe00H * OH and O bounded with Fe were not analysed
Opaque phases include troilite, taenite
, tetrataenite, kamacite, chromite and ilmenite.
The size and composition of grains of the iron-nickel mineral taenite are related to the rate at which they cooled from high temperatures.
However, meteorites rich in solar-wind-implanted gases (and thus presumably from asteroids' surfaces) contain taenite grains with widely varying cooling rates: some dropped only a few tenths of a degree per million years, others did so thousands of times faster.
Occurrence: Associated minerals are: kamacite, taenite
, troilite and forsterite.
Iron meteorites will show a distinct Widmanstatten pattern, the interplay of the nickel-iron alloys kamacite and taenite
, when a freshly polished interior surface is etched with dilute acid.