Octahedrites

Octahedrites are characterized by an intermediate nickel content (6-17% by weight) and contain both kamacite and taenite. These two metallic minerals occur in a distinctive arrangement of bands intersecting in two, three or four directions, which results in the characteristic Widmanstatten pattern. This beautiful pattern appears conspicuously when a section of an octahedrite is polished and etched in weak acid (usually nitric acid). The larger bands in a Widmanstatten pattern consist of kamacite. This kamacite is surrounded by fine sheets of taenite, while the interslices between the bands are made of plessite, a combination of kamacite and taenite.

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