Survey Gamma Radiation Measurements in Commercially-used Natural Tiling Rocks in Iran

— The gamma radiation in samples of a variety of natural tiling rocks (granites) produced and imported in Iran use in the building industry was measured, employing high-resolution Gamma-ray spectroscopy. The rock samples were pulverized, sealed in 0.5 liter plastic Marinelli beakers, and measured in the laboratory with an accumulating time between 50000 and 80000 second each. From the measured Gamma-ray spectra, activity concentrations were determined for 232 Th (range from 6.5 to 172.2 Bq kg -1 ), 238 U (from 7.5 to 178.1 Bq kg -1 ), 226 Ra( from 3.8 to 94.2 Bq kg -1 ) 40 K (from 556.9 to 1539.2 Bq kg -1 ). From the 29 samples measured in this study, “Nehbndan ( Berjand )” appears to present the highest concentrations for 232 Th,“Big Red Flower (China) ”for 238 U , “ Khoram dareh” for 226 Ra and “ Peranshahr” for 40 K , respectively.