Chicago Rocks & Minerals Society

Return to Articles Page >

Every Rock Has a Story
by Robert Beadle
From: The Pick and Dop Stick, 3/2012
6th Place — 2013 MWF Original AduIt Articles

Ages and ages ago what is now known as Illinois was covered with warm shallow seas. North America was located near the equator. For about 41 million years, layers of limestones were deposited in these areas. During this period of time animals such as mollusks lived and died in the sea. Some mollusks were nautiloids and ammonoids; others were simple bivalves that left shell impressions in the limestones.

Millions of years passed as North America slowly continued to shift northward and the seas gave way to coal-forming swamps. Illinois, still near the equator, began to experience a series of uplifts. Hot brines began to form mineral deposits in the areas that would become southern Illinois. Minerals such as galena, sphalerite, calcite, fluorite and others began to crystalize in the cavities between layers of limestones.

Ages passed and dinosaurs walked the earth, only to be eventually wiped out by an asteroid. Finally, strange-looking creatures known as humans became the dominant form of life upon this planet. These humans began to use minerals to change their environment, make life easier, and to comprehend beauty in crystalline shapes.

A long time ago, miners in southern Illinois broke into a vug with mineral crystals and saved it from the ore crusher. The miner kept a specimen of galena and sphalerite knowing that mineral collectors would desire it. Time passed on. Dorothy M. and her husband Mac came down from Chicago and acquired it along with many other specimens for their collection. Many years later, Dorothy placed the specimen in the Chicago Rocks and Minerals Society silent auction. Robert Beadle purchased it because he was building a collection of southern Illinois mineral specimens. Then one day, turning it over he found the small impression of that mollusk that had lived so very, very long ago. It makes you wonder what stories we will leave behind.

For permission to reprint this article, contact us at info@chicagorocks.org.

Return to Articles Page >