Igneous Rock Naming
In many of my articles, I refer to rock names, especially igneous rocks, those produced from magma and volcanoes. Hence this guide to rock naming.
Igneous rocks are classified on the basis of texture, mineral composition, and chemical composition. The naming conventions can get very complicated and controversial. I present below two systems beginning with the simplest. As an example for naming, granite, a plutonic rock, one that cools very slowly and has time to crystallize minerals, has the same composition as rhyolite, a volcanic rock that cools fast. The two differ only in texture.
The next three charts go together. The classification is based on mineral composition of relative content of quartz (silica) and feldspars (sodium, potassium and calcium silicates).