You have entered the Lake Superior Agate gallery. These Lake Superior agates are top grade and many are rare variations. The exceptional glass mirror finish is obtained by running a full month on 600 grit and polish. The formation of Lake Superior Agates began over 1 billion years ago making them the oldest agates on Earth. Lava flows poured out of rifts in what is now the Lake Superior region. Hundreds of lava flows accumulated into mountains of basalt. This sudden accumulation of billions of tons of rock actually pushed a depression in the earths crust. This depression later became the Lake Superior basin. As the lava cooled internal steam and carbon dioxide bubbles were trapped in the lava. Mineralized water percolated through these cavities depositing layers of silica (SiO2). Cooler temperatures allowed chalcedony or agate to form in layer after layer. High temperatures cause quartz crystals to form. Erosion over the next billion years disintegrated the mountain of softer basalt leaving behind the harder quartz and agate nodules. Finally, 2 million years ago the ice age began. A series of glaciers scattered agates from Minnesota to Kansas. The internal motions of the glaciers abraded, fractured and rough polished the agates. As the glaciers melted, rivers and lakeshores further abraded the agates. Iron within the agate reacting with oxygen produced colors ranging from red to brown. The vivid spectrums of colors make Lake Superior agates one of the most beautiful and sought after agates in the world. Please enjoy.