Powder X-ray diffraction pattern and optical images of natural pyrite (FeS₂)

This dataset contains powder X-ray diffraction (XRD) data and complementary optical images of a natural pyrite (FeS₂) sample (sample02_I2_pyrit), purchased in Berlin a small antique and antiquariat store. The measurements were performed at Empa Switzerland in order to characterize the crystal structure and phase purity of the material. Part of the crystal was broken off and ground to powder in a mortar with pestil. The powder XRD pattern exhibits the characteristic reflections of cubic pyrite (space group Pa3̅), including the main peaks at approximately 2θ ≈ 33° (200), 37° (210), 40.7° (211), 47.4° (220), 56.3° (311), 59° (222), 61° (023), 69° (321), and 75° (400). The most intense reflection corresponds to the (311) plane, which is typical for pyrite. The diffraction pattern is fully consistent with the reference data for FeS₂ (e.g. ICDD PDF 42-1340). No additional diffraction peaks attributable to secondary phases (such as marcasite, pyrrhotite, magnetite, or iron oxides) are observed, indicating a high phase purity of the sample. The relatively narrow peak widths suggest good crystallinity and a large average crystallite size. Optical images of the bulk crystal show a metallic luster and blocky morphology typical of pyrite. The powdered sample exhibits a silvery metallic appearance, consistent with freshly ground FeS₂. The dataset can be used as a reference for phase identification, crystallographic analysis, and comparison with other iron sulfide materials in mineralogical and materials science studies.