Agate
var. of Chalcedony
silicon dioxide
SiO2
Amethyst Geode with Agate Shell and a Single Clear Quartz Crystal
Dugway Geode Beds, Utah
Collected on 27 Aug 2006
Complex Amethyst Geode
Dugway Geode Beds, Utah
Collected on 27 Aug 2006
Amethyst Geode with Agate Shell
Wolf Creek, Colorado
Collected on 8 Oct 2008