Climbers are amateur geologists. Rock type can not only dictate how a climber moves up a certain feature but what gear will be required to adequately protect the route in case of a fall. Sandstone is soft but can form dependable and uniform cracks while granite, known for its hardness, often forces climbers onto smooth faces that require moves on features as thin as potato chips. When you put trust in one quartzite crystal to hold your foot or a solution pocket for three fingers to cling to the wall you become uniquely acquainted with your environmental and gain a profound sense of place.
While driving down I25 in Denver last fall I looked west to the Front Range and knew that within those mountains is a canyon, where, 14 miles up the road is a shallow section in the stream which can be easily crossed. There, above a short scree field is a rock face about 35 meters tall hanging over the canyon. On the Southwest facing upper 1/4 of that that rock outcrop a small crack begins to form and widens as it climbs upward. If you were to reach into the widest portion of the crack you would find a small but crisp edge on the left side. I know that small crack well because I held onto it as hard as I could for a what seemed like half a lifetime while my mind race to commit to the move which required me to move away from the safety of that little edge in the crack. I would reach high but return to where I knew I could be assured a secure grip against the wall. Somewhere up above me would be another feature just as solid but I didn't know where or how to get to it. For that amount of time that one feature was my safe place and I can always look at the mountains from anywhere in Denver and know that it is there.