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NWA6259 (Ni-rich Ataxite)
A mass of 1805 grams was found in
northwest Africa in February of 2010.
This iron meteorite is of special
interest because it contains ~42 wt.%
Ni, one of the highest Ni contents of
all irons. This sample is strongly
magnetized, and will actually attract
ferrous materials. The high Ni contents
and magnetic properties suggest that tetrataenite is a major mineral, and
this inference is supported by the
strong optical anisotropy of the metal.
Photos by
Mirko Graul, used with permission.
Apparent length versus orientation for
intragranular needles (likely phosphides)
in NWA6259, digitally measured from five
photographs each collected at a
different region of the sample.
The photos are color-coded. Angles
were measured relative to the
photograph's horizontal. The
apparent length of a needle depends on
its orientation relative to the cut
surface. A needle cut
perpendicular to its major axis appears
as a point (zero length), whereas a
needle cut parallel to its major axis
has maximum length. In spite of
the apparent polycrystallinity of
NWA6259, the intragranular needles tend
to form clusters, with fairly
well-defined gaps between the clusters.
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