sedimentary
Lake Superior Agate
Silicon dioxide, SiO2
AI-generated identification · may be incorrectHardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, displays characteristic concentric banding in earthy tones, and has a cryptocrystalline structure.
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Physical properties
Hardness of 6.5 to 7 on the Mohs scale, waxy to vitreous luster, displays characteristic concentric banding in earthy tones, and has a cryptocrystalline structure.
Formation & geological history
Formed through the deposition of silica-rich groundwater within gas cavities of ancient basalt lava flows over a billion years ago.
Uses & applications
Widely utilized in jewelry making, lapidary arts, and highly prized by rockhounds and mineral collectors.
Geological facts
These agates are the official gemstone of Minnesota and feature rich red, orange, and yellow banding caused by iron oxidation.
Field identification & locations
Identified by waxy concentric bands and conchoidal fracture, commonly found in glacial drift, gravel pits, and beaches around the Lake Superior region.
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