Diffraction contrast in X-ray radiographic images of octahedrite meteorites

Slices of ∼12 mm thickness cut out of an octahedritic iron–nickel meteorite of the Gibeon shower were investigated by conventional X-ray transmission radiography. When the direction of the incident X-ray beam is parallel to one or two of the four habit planes of the kamacite lamellae, black–white contrast lines are observed in the radiographs. These lines are attributed to Bragg reflection, at lattice planes parallel to the lamellae planes, of a narrow band of wavelengths filtered out of the incident white spectrum by absorption in the sample.