The classification of igneous rock is based on a few criteria. What are they?

Minerals Available in Rock

Texture

Color

Chemical composition

Explanation:

There are different criteria that could be used to classify rocks that are igneous. These are:

1) Minerals Available in Rock: The minerals in a rock and their relative proportions in the rock mainly rely on the magma's chemical composition.

2) The Rock's texture: Rock texture largely relies on the magma's cooling history. Thus rocks with the same chemical composition and presence of the same minerals could have very distinct textures.

3) Color: A rock's color relies on the minerals and the size of the grain. Generally speaking, rocks containing lots of feldspar and quartz are light colored, and rocks containing lots of pyroxenes, olivines and amphiboles (minerals of ferromagnesium) are dark colored. But when applied to rocks of the same structure but distinct grain size, color can be misleading.

4) Chemical composition: The most distinctive characteristic is the chemical composition of igneous rocks. The structure generally represents the magma's structure, thus providing data about the rock's source.