## 1 Introduction  
In light of the presence of cosmogenic radionuclides and primordial radioisotopes in the Earth's crust, environmental natural radioactivity is the main cause of the population's exposure to ionizing radiations [1]. Nuclides from the radioactive chains of \({}^{238}\)U, \({}^{232}\)Th, \({}^{235}\)U, and primordial \({}^{40}\)K are noteworthy from the viewpoint of natural radioactivity [2]. Common environmental matrices holding these naturally occurring radioisotopes include water, soil, and rocks [3, 4], the last of which can be used as materials for construction. Thus, investigations on the amount of naturally occurring radioactivity in rocks offer crucial instruments for assessing the radiological risk that humans face from ionizing radiation exposure [5]. This endeavor becomes critical because, as the literature states [6],prolonged exposure to uranium and radium can result in various health effects, such as acute leucopoenia, anemia, oral necrosis, and chronic lung diseases; on the other hand, exposure to thorium can lead to leukemia and cancers of the pancreas, liver, kidney, lung, and brain [7]. Additionally, chronic exposure to radon gas (\({}^{222}\)Rn) may increase the risk of lung cancer [8]. Indeed, only smoking in the general population is a greater risk factor for lung cancer than radon and its daughters, according to the World Health Organization (WHO) [9; 10]. Therefore, it is crucial to continue keeping surveillance on the amounts of radon and its progeny in the environment in order to assess the threats to human health associated with the radiological risks [11]. Although construction materials with large activities of \({}^{226}\)Ra may represent another important source of natural radiation [12], given that \({}^{226}\)Ra decays to \({}^{222}\)Rn in the \({}^{238}\)U decay chain, the pressure-driven influx from subterranean soil is the primary source of indoor radon. Radium and/or uranium traces range from 2 to 4 parts per million (background) to 1000 parts per million (black shales) in various types of rocks [13]. Within the category of igneous rocks, crystalline rocks with a higher probability of containing uranium include granites, granite pegmaties, and syenites [14]. In these rocks, trace minerals such as zircon, monzite, and allanite contain most of the uranium/radium content [15]. The exhalation of \({}^{222}\)Rn from a particular rock surface is significantly influenced by the petrographic and petrophysical properties of the rock itself, even if studies of U/Ra activity might provide useful information on radon release potential [16]. Therefore, to determine the actual risk associated with a particular natural stone, real-time measurements of \({}^{222}\)Rn emission rates are required [17]. Lastly, geochemical analyses of rocks can shed light on elemental distribution patterns, which are then connected to the current environmental state of a particular region [18].  
In this framework, a multidisciplinary approach was used in this work to determine the activity concentration of natural radionuclides in stone samples of particular historical-artistic interest from Noto, Comiso, and Mendicino, Southern Italy, presented as a case study. The results were then correlated with the mineralogy and geochemistry of the samples. In the study locations, they were mostly employed as building materials [19]. Several analytical techniques were used in the multidisciplinary approach, including the Closed Chamber Method (CCM) [20] with the Durridge Rad7 apparatus for short-lived radon progeny alpha spectrometry, High Purity Germanium detector (HPGe), X-ray diffraction (XRD), and Micro-Raman Scattering (MRS) spectroscopy. To calculate the possible danger to radiological health associated with radiation exposure from the investigated rocks, further calculations were made to evaluate the absorbed gamma dose rate (D), activity concentration index (ACI), and alpha index (I\({}_{\alpha}\)).