KAMACITE
Kamacite – (Fe,Ni) – is a Ni-rich variety of native iron. It is abundant in Fe-Ni meteorites (siderites) and also occurs in most other types of meteorites, with the exception of some rocky meteorites. It does not occur in terrestrial geological situations and will not be discussed here in detail.
May contain Co, C, P and S. One variety is called wickelkmamzite, occurring around accessory constituents in meteoritic irons.
1. Characteristics
The physical properties correspond to those of native iron.
2. Geology and Deposits
Occurs only in meteorites.
3. Mineral Associations
Associates with olivine, taenite (Fe,Ni), troilite (FeS), native iron, schreibersite ((Fe,Ni)3P), wüstite (FeO), brezinaite (Cr3S4), plessite (intergrowth of taenite and kamacite) and goethite.
4. Transmitted Light Microscopy
Not applicable, as kamacite is completely opaque.
5. Reflected Light Microscopy
Sample preparation: : the preparation of kamacite is equivalent to that of native iron.
The characteristics are the same as native iron:
PLANE POLARIZED LIGHT – PPL
Reflection color: Medium gray with a brownish tone.
Pleochroism: No.
Reflectivity: ~20%
Bireflectance: No.
CROSSED POLARIZED LIGHT – XPL
Isotropy / Anisotropy: Isotropic, completely dark throughout the rotation of the stage.
Internal reflections: No.
May be confused with: other minerals that occur in meteorites. See specific literature.
