In this study, the classification of the risk of new safety slip of the pedestrians in natural stone floor covering when barefoot and walking with shoes. A total of 15 types of natural stones were categorized according to and subjected to their geological, mineralogical-petrographic, chemical, physical, and mechanical characterization tests. Coefficients of friction (COF) have been found by the natural stone formed four surface processing techniques (SPTs), three environmental conditions, ramp and pendulum test device, and DIN EN 51097, DIN EN 51130, and TS EN 14231 standards. The new slip safety risk scale is determined by the K-means method considering the wet (WE), dry (DE), and lubricated (LE) environmental conditions and the applied SPT of the parameters affecting the COF values of natural stones. With the data obtained from the tests, the slip safety risk scale of the COF of natural stones was determined by the statistical K-means clustering method. According to statistical results, natural stones have been classified according to three slip test depending on their COF values.