To add a little fun and hands-on activity to your classes, take a look at these 46 different experiments that you can use in your classes or have your students complete at home. They are simple and most are low- or no-cost activities that can be done quickly and teach a lesson in geology.
My favorite on this list would be this "gem" of a resource! Produced by the Colorado Department of Education, this booklet includes some lessons and resources for you, but the best part is the "Teacher Background Information," starting on page 4, that will help you make sure you are up to speed on the topic.
Make sure you click on the "Play a Song for this Topic" button at the top of the page to hear a great song about rocks and minerals! Then, proceed through the presentation explaining all about the earth's layers and rocks and minerals.
This is an excellent database of various types of rocks that you and your students can use to identify rocks or learn more about each type. When you click on each type, a full page opens with everything you ever wanted to know about that type of rock. (BONUS: On the left side of the page is a list of all 50 states. Clicking on one will bring up a page with a collection of maps for that state.)
You will find some interesting information on teaching about rocks and minerals in this article. Specifically, it talks about why and how to teach when your district's requirements differ from the science standards. As an extra, there are links to lessons and other resources for teachers.