We take our learning at CIS very seriously.  We also like to make it fun.  Mrs. Schmidt helps students learn about geodes.  A geode is a round rock which contains a hollow cavity lined with crystals.
They even made edible geodes!  (no teeth were chipped in this experiment)
Studying the different layers of the geode.

The most common dissolved mineral is quartz, but amethyst and other minerals are also found. It can take hundreds of millions of years for the space inside a geode to be filled, and many geodes remain partly hollow. A geode which is completely filled with crystals is called a nodule.