The present study reports about the fluoride containing minerals present in the rock and soil samples collected from the fluoride endemic region of Gaya district of Bihar. Fluoride was measured in 77 water samples collected from fluoride endemic villages and 69 samples contained fluoride> 1.5 mg/L. A positive correlation was found between pH and fluoride (r= 0.24), suggesting geogenic contamination of fluoride into groundwater. X-ray diffraction (XRD) analyses of rocks and soil samples were done. Results showed the presence of biotite in the rock and soil samples, suggesting that F might be leaching from biotite into the groundwater.