The rock samples you encountered while completing this exercise are called hand samples because you can pick them up in your hand and study them. You can also easily examine hand samples with a hand lens, test them for hardness and reactivity to HCl, and feel or heft. However, some characteristics of each rock group are so diagnostic that you can observe them at a distance and classify the rock as igneous, sedimentary, or metamorphic. Examine the rock outcrops shown in the above figure and determine whether each is igneous, sedimentary, or metamorphic.