GO 324A Rocks and Minerals
ES 567A Hand Specimen Petrology
Dr. Susan Ward Aber

Emporia State University
Emporia, Kansas USA
Earth Science Department


Spring 2011 class at Rose Dome, Woodson County.
Photo by J.S. Aber; photo date 4-19-2011.

Welcome to Rocks and Minerals!

Minerals are the main constituent of rocks and are naturally occurring, macroscopically homogeneous, and solid substances with a definite chemical composition and crystalline structure. It is usually assumed minerals are of an inorganic origin, but exceptions occur as in the case of pearl. A mineral may be simple, such as copper, which is a native element composed of... copper! A mineral may be complex, such as tourmaline, a silicate of boron and aluminum composed of Na (Mg, Fe)3Al6(BO3)3(Si6O18)(OH, F)4 with a ring-silicate or cyclosilicate crystalline structure.

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.

This course involves the scientific study of rocks and minerals, which is called petrology and mineralogy! Specifically, petrology is the natural history of rocks including origins, present conditions, alterations, and decay. It is made up of petrography, the study and description of rocks and minerals in thin section, and petrogenesis, the origin of rocks. Considering that rocks are natural aggregates of minerals, it is easy to understand why the course begins with mineralogy, the study of minerals!

There are over 4,500* 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!

Links of Potential Interest:

  • Impossible crystals are 'from space' http://www.bbc.co.uk/news/science-environment-16393296 , and you may blend in two stories on the same theme, Strange Crystals Reveal Rock to be Ancient Meteorite, http://news.yahoo.com/strange-crystals-reveal-rock-ancient-meteorite-205104508.html and Nobel win for crystal discovery, http://www.bbc.co.uk/news/science-environment-15181187
  • Secrets of Salt, http://www.pbs.org/wgbh/nova/earth/secrets-salt.html
  • Elephant Week: Poaching and Ivory Smuggling at Record Highs in 2011 and the summary should include whether ivory is a rock, mineral, or what? http://blogs.scientificamerican.com/extinction-countdown/2012/01/03/elephant-poaching-ivory-smuggling-record-highs-2011/
  • the interactive online video of Spirit and Opportunity rover excursions, http://www.pbs.org/wgbh/nova/mars/upclose.html. You must launch interactive video (hearing it is best but there is a printable version as well); be sure to include rock types found and instruments used on Mars to detect the rocks and structures.
  • Hawaii Volcano has been Erupting for 29 Years, and in the summary record the 10 biggest volcanic eruptions in history, as well as image 8 in the volcanoes from space, http://www.livescience.com/17746-kilauea-volcano-eruption-29-anniversary.html
  • Anatomy of a Volcano, http://www.pbs.org/wgbh/nova/earth/volcano-parts.html

    * According to the Commission on New Minerals, Nomenclature, and Classification, there are...

    Recommended References and Links

    Return to the top.

    Petrology Introduction
    Sedimentary Rock
    Metamorphic Rock
    Course Field Trip
    Course Syllabus
    Class and Field Trip Specimen Collection

    This page originates from the Earth Science department for the use and benefit of students enrolled at Emporia State University. The curriculum is © by the author, 2001-2014. Last update January 21, 2014. For more information contact Dr. S. W. Aber, e-mail: esu.abersusie@gmail.com or Dr. Aliva Allison, email: aalliso2@emporia.edu

    To understand copyright, visit www.copyright.gov/. All rights reserved. Susan Ward Aber.