Library EventGeodes! Iowa’s Mysterious State Rock

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Wednesday, June 27, 2018 - 7:00pm to 8:00pm

06/27/2018 7:00pm 06/27/2018 8:00pm Geodes! Iowa’s Mysterious State Rock Ray Anderson from the Cedar Valley Rocks and Minerals Society will be here share the secrets of this most mysterious of rocks. Say the word Geode and most people picture a hollow rock with crystals in side. Iowa geodes are lumpy round or oval shaped rocks that looks kind of like lumps of cauliflower. Most are two to six inches across, although a few geodes larger than thirty inches have been found. Geodes can be hollow, with only a thin layer of crystals, or filled solid with crystals – or anywhere in between. Quarts and Calcite are the most common types of crystals, but at least 25 different minerals have been found in Iowa geodes. Geodes can be found in many places in the United States, but they are the official State Rock of Iowa! The most prized geodes with the largest variety of minerals are found in Mississippian rocks in the Keokuk area, the fabulous “Keokuk Geodes.” Geologists are still not certain how these beautiful and mysterious geologic wonders form. We will discuss Iowa geodes, and geodes from other areas, how they may have formed, and see photos and real specimens of some beautiful examples. Who knows, we may even crack a few open to discover the treasures inside. This program is part of ICPL's 2018 Adult Summer Reading Program Iowa City Public Library Iowa City Public Library America/Chicago public

Meeting Room A, Meeting Room B, Meeting Room C

Ray Anderson from the Cedar Valley Rocks and Minerals Society will be here share the secrets of this most mysterious of rocks.

Say the word Geode and most people picture a hollow rock with crystals in side. Iowa geodes are lumpy round or oval shaped rocks that looks kind of like lumps of cauliflower. Most are two to six inches across, although a few geodes larger than thirty inches have been found. Geodes can be hollow, with only a thin layer of crystals, or filled solid with crystals – or anywhere in between. Quarts and Calcite are the most common types of crystals, but at least 25 different minerals have been found in Iowa geodes. Geodes can be found in many places in the United States, but they are the official State Rock of Iowa! The most prized geodes with the largest variety of minerals are found in Mississippian rocks in the Keokuk area, the fabulous “Keokuk Geodes.” Geologists are still not certain how these beautiful and mysterious geologic wonders form. We will discuss Iowa geodes, and geodes from other areas, how they may have formed, and see photos and real specimens of some beautiful examples. Who knows, we may even crack a few open to discover the treasures inside.

This program is part of ICPL's 2018 Adult Summer Reading Program

If you need disability-related accommodations in order to participate in this event, please contact the Library.

This event is open to the public.

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Cosponsor

Cosponsor Organization: Cedar Vally Rocks & Minerals Society

Cosponsor Name: Ray Anderson