Humans have always been exposed to different types of natural and cosmic radiation. At present we experience 83 % natural radiation, for example from granite marbles, building materials such as concrete, brick, granite, or drywall. However, although these are potential sources of radon, they are rarely the cause of a high level of pollution in a building.Ashlar is a material of volcanic origin comprising heterogeneous and solidified detrital pyroclastic materials such as rhyolite, sand, volcanic ash and pumice, among others. Chemically, ashlar is principally composed of elements such as sodium, magnesium, calcium, iron, aluminum, sulfur, and cobalt. In order to identify the presence of these elements in the ashlar, X-ray Fluorescence studies were carried out first, using modern XRD and XRF equipment, followed by quantitative analysis using a neutron activation technique, and finally, low-level gamma spectrometry to evaluate the presence of radioactive elements.