The aim of this study is assessing the concretes containing olivine, which is an abundant and locally mined mineral in Turkey, in terms of several essential photon shielding parameters, which are total mass attenuation coefficients (/), mean free paths (mfp), half and tenth value layer thicknesses (HVL and TVL, respectively), effective atomic numbers (Z(eff)), and electron densities (N-el). For this purpose, two types of concretes with and without olivine content have been produced and studied by photon transmission experiments, simulations and theoretical calculations. In the experimental part, photon transmission technique has been performed using a 16k 3 x 3 NaI(Tl) detector system and so, /, mfp, HVL, and TVL values of concretes have been determined experimentally at 511 and 1275 keV photon energies. Aforesaid parameters have also been estimated by simulations at the same energies using Geant4 Monte Carlo code. For theoretical calculations, the web version of NIST XCOM photon cross-section library has been utilized. By this way, all parameters have been calculated at 1 keV-100 GeV energy region and compared with data from experiments and simulations. It has been observed that olivine addition affected the aforementioned radiation shielding parameters of concretes positively at 511 and 1275 keV energies. Also, results from each method have been found to be in a reasonably good agreement, especially for the ones from XCOM and Geant4. So, it has been concluded that Geant4 code is a powerful tool in such studies.