by Kate Redpath
"Look at this one!" Rob Grinde calls. "I found another billion-year-old beauty."
Rob is a 14-year-old agate hound—someone who hunts for agates. Agates are rocks, and rocks are made of minerals such as quartz and hematite.
Rob and his friends are looking for Lake Superior agates in northeastern Minnesota along the Kettle River. They follow the winding shoreline, stopping to dig through gravelly beaches and pull stones from shallow water. Carrying small shovels and sacks, they crawl along the water's edge to get a closer look. Sometimes they reach down into the mucky river bottom to see what they find.
The agate Rob just found really is 1 billion years old. Because it has been buried under ice or water or soil for most of that time, Rob might be the first human to touch it.
Whether young or old or in-between, agate hounds get excited when they find a Lake Superior agate, named the state gemstone in 1969. Agates are called gemstones because people cut and polish them for jewelry. These remarkably beautiful rocks are part of the history of the volcanoes and glaciers that shaped Minnesota's landscape.
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