|Gneiss. A banded foliated metamorphic rock with coarse grain.|
First color. Is the rock light, medium, or dark colored? Of course these are generalizations and the rock might be pinkish or tan or brown. But, even if it is pinkish it is likely a light colored rock such as granite, quartzite, or possibly rhyolite. The rock may also have both dark and light specks through out it. If the rocks are sort of an even "salt and pepper", with approximately even amounts of light and dark, it would be considered medium in color, such as diorite. Even light colored rocks will have some dark specks in them or dark colored rocks some light colored specks. The key is determining the overall generalized color of the rock.
|Granite. A coarse, light colored igneous rock.|
Third, what is the overall structure or pattern of the rock. Does the rock show irregular banding patterns such as gneiss, or no pattern such as with granite? Does the rock break into plates like with schist or slate? Or are there many long parallel bands which are called bedding planes such as with sedimentary rocks like limestone.
|Limestone. A light colored sedimentary rock that forms bedding planes. No bedding planes visible in this picture.|
|Sandstone cliffs. A coarse textured sedimentary rock made or sand. Individual sand crystals do not interlock. Sandstone forms bedding planes that run parallel to each other as seen in this picture.|