Evaporation of saline solutions from a porous medium often leads to the precipitation of salt at the surface of the porous medium. It is commonly observed that the crystallized salt does not form everywhere at the porous medium surface but only at some specific locations. There is also more salt accumulation in one zones than in others. In this project, two experiments are going to be made to study this phenomenon. In a first experiment, efflorescence formation is considered at the surface of an homogenous porous column inside a hollow cylinder, while water from a salt solution is evaporating. The mass, the temperature and the hygrometry are measured periodically during the experiment, and photos are taken too every 10 minutes. Moreover, scanners of the sample are also done periodically. With the data obtained by the scanners and using the Matlab software, some graphics are going to be obtained which will permit us to analyse the sample as time goes by and also the characteristics of the final sample, once all the water has evaporated. In a second experiment, a comparison is going to be made between the final salt crystals formed in different samples. These samples differ between them because they have different quantities of salt solution, they are in different sample containers or they can have or not have a porous medium. All of these different samples are going to be put into an oven to completely evaporate all the water they have, and finally, different salt crystals are going to be obtained, analysed and compared between them. After doing this two experiments, some conclusions about efflorescence are going to be drawn.