Sophia Learning
Sophia: Geology: Geodes: Lesson 1
This lesson will present how to identify and classify geodes. It is 1 of 2 in the series titled "Geology: Geodes."
3D Toad
3 dtoad.com: Special Geology
A 3-D view of special geological rocks including Anhydrite, Azurite, Celestite, Fluorite, Kyanite, Opal, and Quartz Geode.
Indiana University
Indiana University Bloomington: Geo Notes: Geodes: One of Nature's Mysteries
Explains what geodes are, how they form, and where they can be found in Indiana.
Indiana University
Indiana University: Reference Documents: Geodes: One of Nature's Mysteries [Pdf]
A fact card describing the properties and characteristics of geodes, where they can be found, and how they may have formed.
Sophia Learning
Sophia: Geology: Rock Classification Overview
Understand how to classify rocks and minerals with this concise tutorial.
Curated OER
National Park Service: Agate Fossil Beds: Geologic Formations
This National Park Service site has information about these fossil beds in Nebraska and where the name Agate came from.