This is a porphyritic rock. This is a porphyritic rock. Diorites contain sodium plagioclase. This is a phaneritic rock. This is a phaneritic rock.
Gabbros contain calcium plagioclase.
Diorites contain sodium plagioclase. You seem to understand this concept. With this Internet exercise you will have an opportunity to work with photographs of igneous rocks. There are two fundamental properties of igneous rocks that are used to assign a name. The higher the rate of cooling the smaller the size of the crystals.