Rare Gems and Minerals in Iowa

The state of Iowa is more known for corn than it is for its minerals. This is perhaps because most land in the state is devoted to the production of corn and other agricultural produce. However, there are quite a number of unique and interesting gems and minerals that you can dig up in the state especially along rivers and in river valleys and basins.

When it comes to mining, Iowa is primarily known for having geodes, but you can also find fossils and several different types of minerals. Quite a number of meteorites have been discovered in the state, which makes Iowa an interesting state for meteorites hunters also, which are primarily found by metal detecting.

Here are some of the favorite gems you should expect to find in Iowa.

Keokuk Geode

This is the most important gem you can find in Iowa. The Keokuk Geode was named the state's official rock in 1967. This is perhaps why Iowa is known more for its geodes as opposed to any other gems.

Keokuk geodes are mostly spherical in shape and sometimes cauliflower-like or lumpy with a diameter ranging from two to six inches, although diameters of up to thirty inches have been recorded. Most of the geodes in Iowa are in the form of limestone formations and usually have hard outer shells.

Although quite a large number of geodes that people discover in Iowa are solid with crystal-like minerals filling the interior, some of the best geodes that you can find have hollow interiors. Some of the geodes mined in the Keokuk area in the state usually contain a wide variety of minerals although calcite and quartz are the most dominant.

You can also find some geodes from the southern region of Iowa.


Freshwater pearls are found in some waters in Iowa. If you are looking for pearls, then all you have to do to hunt them is to find the shelled mollusks found in both slated and fresh Iowa waters.

The pearls are smooth, round stones that shows an iridescent white, pinkish, or silver appearance. Although they are quite rare in some waters, these amazing stones can be found in many places within the state.

Moss Agate

This is a rare form of Quartz pseudomorph, especially in Iowa. The availability of natural chalcedony in Iowa makes the start a fertile ground for the occurrence of Moss Agate. Usually, impurities in the chalcedony cause these interesting formations.

As the name suggests this is not a pure agate because it does not have the multicolored banding that a typical agate would have. However, the chemical change in the stones allowing for the substance to grow allows for the classification of the substance separate from both agate and the chalcedony and it is quite an important collectible gem.


This is another important semi-precious gemstone that you can find in Iowa. It is a type of quartz that sometimes is not considered as a different item by gem collectors. Most of the chalcedony is either white or blue even though a few variations occur. It is an important collectible that sometimes is used for decorative purposes.