Weathering on rocks is an important component of the world’s geomorphology. One way to measure weathering on rocks is to analyse rock hardness. This is a study conducted in the northern hemisphere on granite rocks in Uppsala, Sweden. A Schmidt hammer is used to create a correlation analysis between the aspects on three glacial erratic boulders and rock weathering. Statistics from the Schmidt hammer were then collected and analysed. The results showed a difference between the aspects of the rocks. Although only small differences between the rocks were found, the south and south-east aspects of the rocks were softer and suffered from a more dynamic rock weathering than the north aspects of the rocks. The reason to the more dynamic weathering on the south facing aspects is suggested to be because of a more dynamic thermal stress weathering. The same reason caused the north aspect to have a steeper slope and a more dense lichen cover.