Abstract: In this thesis exploration methods for brick production in the case of Karlovac brick plant are presented. The raw material is exploited from the nearby quartz sand deposit “Brezovi Rebar” and clay deposit “Rečica”. In addition to existing research that has been done for the purpose of determining the quality of raw materials, quantity of the reserves, and genesis of quartz sand deposit and clay deposit, additional research was conducted for the needs of this thesis aiming to obtain more detailed information about the composition of the raw materials. A total of 16 samples was analysed, 13 samples of them were taken from the quartz sand deposit, and 3 from clay deposit. Granulometric analyses, X-ray powder diffraction analysis of global sample, determination of iron content, humidity, eand determination of color were performed on 8 sand samples. Limonite crust samples (two samples), that are randomly distributed as thin layers within the deposit of quartz sands were analyzed using X-ray powder diffraction.. Detailed x-ray powder diffraction analyses of global clay samples and clay fraction (<2 μm) as well as granulometric analysis were conducted on specimens from clay deposit. Rock underlying quartz sands was analysed using x-ray powder diffraction and petrographic microscope. In the samples of quartz sand, the dominant iron oxide is goethite, and secondary (in the sample of limonite crust) is lepidocrocite. The main mineral phases in the clay fraction of clay deposit "Rečica" are illitic material, well-crystallized kaolinite, smectite, vermiculite and chlorite. These analyzes have increased the current state of knowledge about the composition of investigated minerals resources. The methods of calculation of reserves, the quantities of the reserves, the quality of raw materials, and the process of brick manufacturing are also presented in the thesis.