Arsenopyrite is opaque and spectrally featureless. Its opacity is caused by the conduction band extending over the entire range, mainly due to the presence of arsenic. The contaminants in this sample are not abundant enough to alter this behaviour, and the fact that the largest paritcle size falls approximately in the middle of its reflectivity range has no real significance. Unindexed reflections could not be identified, suggesting they may represent more than one phase. Peaks are symmetric and of normal width, but alpha1-alpha2 wavelength resolution is poor.
Phases are only moderately crystalline.
Optically opaque, grayish yellow metallic luster. Suggest magnetic separation be done on this sample.