In this thesis the fracture mechanical behaviour of industrial manufactured refractories is investigated by means of a mini wedge splitting test. The advantages of the mini wedge splitting test compared to the regular wedge splitting test are the more stable crack propagation, due to the smaller sample size, and the possibility to investigate the crack propagation with a microscope. Fracture mechanical parameters like specific fracture energy and notch tensile strength are calculated for magnesia, spinel and two zirconia products. The crack initiation is investigated with a stereo microscope and the crack propagation with digital image correlation. The results show that the mini wedge splitting test is suitable to investigate relative brittle materials like the two zirconia products, due to the fact that stable crack propagation is obtained. Also the crack initiation and propagation for aforementioned products is investigated with a stereo microscope. The load displacement curves, the fracture mechanical parameters und the results for crack initiation and propagation are shown. Furthermore, the fracture mechanical parameters of the mini wedge splitting test are compared to results from the wedge splitting test suggested by Tschegg. As expected, the results for the specific fracture energy for magnesia products are considerably lower for the mini wedge splitting test compared to the wedge splitting test suggested by Tschegg. This is due to a constrained fracture process zone in the mini wedge splitting test.