The phase morphology of nickel sulfide (NiS) has received attention because of the possible correlation between fracture of toughened window glass panels and the alpha-beta phase transition. The detection of NiS in situ in glass, however, has proven difficult for a number of reasons, including its small size and dark color, which is ubiquitous among other contaminant stones in glass. The current study employed Raman spectroscopy to characterize NiS in both the alpha and beta forms, because this technique is nondestructive and has the potential for the in situ characterization of NiS. Differentiation between the two forms of NiS was found possible and is discussed in terms of the phase change from a rhombohedral unit cell in the beta form to a hexagonal cell in the alpha form.