GO 324A Rocks and Minerals Dr. Susan Ward Aber www.emporia.edu/earthsci/amber/go324/intro.htm

Emporia State University Emporia, Kansas USA Earth Science Department

Rocks are aggregates of one or many differentiated or undifferentiated minerals. For example, granite is primarily made up of differentiated quartz, mica, and feldspar, and each mineral can be clearly seen in hand specimen. In contrast, limestone consists almost entirely of undifferentiated calcite, where the calcite can be determined through testing but not clearly recognized as a crystal in hand specimen.

There are over 4,000 known minerals, but only about 20 make up some 95% of all rocks. This course will examine some of the more common minerals and rocks, with a focus on specimen identification. Minerals will be presented first because they are the foundation of rocks. Rocks are divided into one of three major classes: igneous, sedimentary, and metamorphic; rock specimen identification will comprise the remainder of the course.

Why is the study of rocks and minerals important? An understanding of Earth's 4.5 billion year history and formation is derived from discovering the differences between rock types and mineral formation. There are primarily sedimentary rocks exposed at the surface in Kansas. However, 1.2 billion year old granite and 88-90 million year old contact metamorphic rocks exposed at the surface in Kansas as well. In addition to exploring and understanding Kansas and the planet we live on, minerals and rocks are of great economic importance and humanity depends on a steady supply to live!