What is a vug?

You have never heard of a vug? Come on, you see them all the time. We've visited very cool vugs at the Botanical Center. There are also scads of them around Rock Hound, GCX7D2, at Saylorville Lake. You probably call them geodes, but when we visited McBride Hall (at the University of Iowa) in the fall, we learned that the proper name for a rock with a crystal-filled cavity is a vug. A geode is a rock unto itself, a hollow, nodular rock, separate from substrate or matrix. Click on the photos, especially the lower one, to see the crystals closer. Pretty cool, eh?

Rock Hound is at a location that my children want to visit all the time. My younger son asks to go there. They enjoy seeing all the flotsam, looking for fossils like brachiopods (did you know that the root brac- means arms? Well, brachiopods evidently had "arms" to sweep food into their mouths.), eggs and animals, and vugs, and having unstructured play. We go to the access point, or trail head, in Prairie Flower campground and have some playground time, but something about the Rock Hound area is more desirable to the kids. And I am OK with that.