In this experiment the ability to resist breaking down due to a strong acid was tested in three different types of rock, granite, basalt, and marble. As can be seen in the chart, marble was by far the worst at resisting break down due to acid exposure. After being exposed for several days to the HCl, it lost far more mass than the other two, losing 28% of its mass on average. In comparison, granite and basalt had very similar resistance to breaking down. After being exposed to the HCl, granite and basalt lost an average of two and three percent mass respectively. It was hypothesized that granite would be the most resilient to acid rain, or HCl in this case. This hypothesis was proven incorrect. The basalt, on average, lost 2% mass, while the granite lost 3% mass. However, this conclusion cannot be considered valid due to outliers and sources of error. In trial one, granite lost far more mass than in any of the other trials, at 7%. This is a massive outlier that most likely threw our data off. Another source of error is that the variable of surface area was not held constant. While the mass lost was as a percentage, rocks with similar mass but more surface area would have much more exposed rock at any time and therefore lose mass more quickly. A third source of error is human error. The rocks used were estimated to have similar surface areas by eye, and were not very accurate. Due to all of this, our conclusions of basalt being more resilient than granite are not valid. The data on marble, however, is very constant throughout all of the trials and can be considered valid. The implications of this are that granite and basalt make better materials for building in areas prone to acid rain than marble, which would deteriorate much more quickly than the others.