The process of natural or spontaneous mummification has been observed for more than a hundred years in various Mexican pantheons. The construction materials used in the niches of the pantheons generate particular microenvironmental conditions that promote the preservation of organic materials. The construction materials (mining adobe, brick and stone material) that make up the three series of the municipal pantheon of Santa Paula were studied and analyzed using X-ray Diffraction, X-ray Fluorescence and petrographic analysis techniques. At the same time, the mechanical and physical properties of the materials were determined, as well as the relative humidity and temperature within the niches. The results indicate that the geochemistry, distribution and percentage of said materials inside of the niches created exceptional microclimatic conditions that favored the conservation of the bodies. With this contribution we intend to advance the understanding of the influence that construction materials had on the process of natural mummification.