4.7" Polished Banded Lake Superior Agate - Minnesota

Lake Superior agate is a variety of agate collected throughout Minnesota. It commonly features red, orange, yellow, and white concentric banding: its red, orange, and yellow colors can be attributed to iron impurities. This makes sense, considering iron is a major industrial mineral found throughout the Cuyuna, Mesabi, Vermillion, and Gunflint Iron Ranges making up much of the northeastern geological regions of Minnesota, along Lake Superior's northwestern shore. They formed by silica- and iron-rich fluid deposition within vesicular pockets, which themselves were created as gas bubbles as the lava around them cooled. Over time, the agate nodules eroded out of the rock and were naturally dispersed by glacial activity throughout multiple regions of Minnesota, Iowa, Kansas, Michigan, Nebraska, and Wisconsin. It is such a prominent mineral with a rich and insightful history that it was designated as the official state gemstone of Minnesota.