Agate
var. of Chalcedony
silicon dioxide
SiO2
![Amethyst Geode with Agate Shell and a Single Clear Quartz Crystal](http://marulla.com/wp-content/uploads/2008/11/imgp064.jpg)
Amethyst Geode with Agate Shell and a Single Clear Quartz Crystal
Dugway Geode Beds, Utah
Collected on 27 Aug 2006
![Complex Amethyst Geode](http://marulla.com/wp-content/uploads/2008/11/imgp066.jpg)
Complex Amethyst Geode
Dugway Geode Beds, Utah
Collected on 27 Aug 2006
![Amethyst Geode](http://marulla.com/wp-content/uploads/2008/10/002.jpg)
Amethyst Geode with Agate Shell
Wolf Creek, Colorado
Collected on 8 Oct 2008