Lake Superior Agates are formed from volcanic rocks that solidified around 1.1 billion years ago

These volcanic rocks were composed of silica-rich lava that eventually cooled and solidified into an igneous rock called basalt. Over time, cracks and voids developed in the basalt, and groundwater that was rich in silica seeped into these cracks. The silica in the groundwater gradually deposited into the voids, filling them and forming agates.

The agates that formed in the basalt near Lake Superior are known for their distinctive colors, which are caused by the presence of iron and other minerals in the silica deposits. Over time, the basalt eroded away, and the agates were exposed and eventually collected by people.

The process of agate formation is a slow one, taking millions of years. However, the end result is a beautiful and unique gemstone that has been prized by people for thousands of years.