Color is an important heritage asset property, giving value and life to historical objects. Colonial paintings require management and control since their constitutive pigments are susceptible to physical and chemical changes due to weather and pollutant conditions. In this regard, simulation and experimental techniques such as X-ray diffraction and scanning electron microscopy were used to determine the aging and composition of a selected mural painting from the colonial period of Cusco, Peru. As a result, hematite is suggested as the pigment used in the mural painting. Meanwhile, Cusco's low humidity environmental conditions in certain seasons favor the transformation of hematite to goethite, modifying the original color of paintings. This research aims to understand the material deterioration of pigments from heritage objects as input for future studies pursuing conservation strategies.