Due to environmental issues, interest and usage of high belite cements has increased in the last few years. Since hydration kinetics and reactions of belite are still quite unknown, this master’s thesis investigates and observes these processes. Using an X-ray powder diffraction (XRD), the basic characteristics of 20 nm – 2 μm belite particles were determined. Using a scanning electron microscope (SEM) in combination with energy-dispersive X-ray spectroscopy (EDS), morphology of particles were studied. Reactions of hydration as a function of time were executed at three different temperatures: room temperature, at temperature of 80 °C and at temperature of 200 °C, and at various time intervals ranging from 6 hours to 42 days. Based on SEM observations and XRD results, several findings were derived. The rate of hydration is affected by size and shape of the original starting material. The temperature also has an important impact on the hydration rate; higher temperatures lead to a higher reaction rate. The mineralogical composition of samples hydrated at room temperature and at temperature of 80 °C does not change during 42 days of hydration. The predominate product in all samples is a nearly amorphous calcium silicate hydrate (C-S-H). Many different morphological types of C-S-H can be found in samples, in some samples even simultaneously. Temperature affect the size of C-S-H III particles, the particles mentioned are smaller in samples hydrated at a higher temperature. However, the size of C-S-H III (C-S-H III is one off the morphological shapes of C-S-H) particles does not change during the hydration progress. Crystallization of calcium hydroxide (CH) begins when the solution becomes oversaturated with Ca2+ in OH- ions. Hydration of pure belite in pure water at room temperature without any added additives proceeds very slowly. In order to develop the strength of high belite cements in an acceptable time frame, the application of specific additives and alloys, permitting an increase in the hydration rate is necessary.