How do I know my stone is an agate? "Agates are sometimes hard to identify, even for the experts," Mary Ann St. Antoine, a senior environmental quality analyst in the Marquette District Office of ...

Known for their colors and patterns, collectors are often amazed at agates that turn up on Upper Peninsula lakeshores, with ...

How do I know my stone is an agate? "Agates are sometimes hard to identify, even for the experts," Mary Ann St. Antoine, a senior environmental quality analyst in the Marquette District Office of ...

The elusive Lake Superior agate. Rockhounds scour Lake Superior’s shoreline for these rare banded beauties—from the western reaches of the Keweenaw Peninsula to the U.P.’s easternmost ...

KALAMAZOO, Mich. — Although building sandcastles and jumping over the waves of the Great Lakes may be a blast, exploring Michigan's shores for ridiculously cool rocks has become a popular ...

Agates are formed inside of rocks made by volcanoes, called igneous rocks. It may take thousands of years for water, thick with the mineral silica, to seep into the rock’s holes and create an agate.

You never know what you're going to get when you crack open a geode-like rock called an agate, but a new specimen is even more surprising than usual: It looks just like Cookie Monster. The agate ...

Oregon's state rock is celebrating its 60th anniversary this year. Here's everything to know about the thunderegg and where to find them in Oregon.