James Madison University
James Madison University: Igneous Rock Classification
This site explores the classification of igneous rocks. Content addresses classification based on color and texture, mineral composition, and chemical composition.
Other
Cal Poly Pomona: Igneous Rocks
If you need a technical summary of igneous rock classification, then this resource is worth checking out. It has several different diagrams to help you visualize the classification process.
CK-12 Foundation
Ck 12: Earth Science: Igneous Rock Classification
[Free Registration/Login may be required to access all resource tools.] How to classify igneous rocks.
CK-12 Foundation
Ck 12: Earth Science: Intrusive and Extrusive Igneous Rocks
[Free Registration/Login may be required to access all resource tools.] Determination of intrusive and extrusive igneous rocks.
Other
Geology.com: Rocks: Photos of Common Intrusive and Extrusive Igneous Rock Types
Explains the difference between intrusive and extrusive igneous rocks and provides pictures and descriptions of common igneous rock types in each category.
Australian Museum
Australian Museum: Igneous Rock Types
Learn about the different types of igneous rocks and how they are classified.
CK-12 Foundation
Ck 12: Earth Science: Igneous Rock Classification
[Free Registration/Login may be required to access all resource tools.] Presents the classifications of igneous rocks based on silica content.
CK-12 Foundation
Ck 12: Earth Science: Igneous Rock Classification Study Guide
A quick review of the basic concepts in igneous rock identification.