There are two different types of rocks next to you (see image). One is magmatic rock, the other a sedimentary rock. Magmatic rocks are divided into two subgroups. One is a coarse-grained intrusive rock also known as plutonic rock. In contrast, when hot magma erupts (Lava) to the surface of the Earth, it crystalizes very fast (cools down fast). Consequently, the minerals/crystals are very fine grained. Almost not visible with naked eye. This later rock (subgroup) is called extrusive rock.
Now, what type of rock is the orange one in the middle of the path way (A)?