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One of the most abundant trace elements present in the Earth’s crust is fluoride, having 625 mg/kg average concentration in different kinds of rock (Edmunds and Smedley 2005; Tavener and Clark 2006). The rocks containing fluoride‐rich minerals are the largest fluoride reserve. According to some studies, the highest fluoride concentrations are combined with quartz, felsic, gneisses, syenites, granites, and alkaline volcanic (Robinson Jr and Kapo 2003; Rosi et al. 2003; Moore 2004; Chae et al. 2006, 2007; Ozsvath 2006). Rocks found in the Coimbatore district of Tamil Nadu contain 180–2600 mg/kg fluoride (Table 2.1). Among various fluoride‐rich minerals, some of them are fluorite (CaF₂), micas, amphiboles, villiaumite (NaF), and topaz (Al₂[SiO₄]F₂). These chemicals are abundantly found minerals in sediments and rocks (Cronin et al. 2000; Saxena and Ahmed 2003; Edmunds and Smedley 2005; Chae et al. 2007).