Iowa geodes have long been objects of curiosity, their sparkling interiors containing some of the most beautiful crystals to be found anywhere in the Midwest. Although geodes are known from many localities around the world, one of the most productive and famous collecting regions is encompassed within a 35-mile radius of Keokuk, Iowa. Rock collectors commonly refer to geodes from this region as "Keokuk geodes." In keeping with the world-renowned status of the Iowa geodes, the Iowa General Assembly declared the geode as the official "State Rock" in 1967.
Iowa Science Teachers Journal
© Copyright 1989 by the Iowa Academy of Science
Witzke, Brian J.
"Geodes: A Look at Iowa's State Rock,"
Iowa Science Teachers Journal: Vol. 26
, Article 6.
Available at: https://scholarworks.uni.edu/istj/vol26/iss1/6