These agates are spread by glacial forces over the middle north of the United staates and are belonging to the oldest agates in the world. They are having their origin in the 1.2 billion year old Great-Rift-Lavaflows.Agate collectors are able to find them near to their place of origin in Minnesota, Wisconsin and Michigan. In Iowa, Illinois, Nebraska, Kansas and Missouri they can be found too.Agate-nodules of this type can be found in gravel-pits or fields.
They show red to brown colours and sometimes a strong “shadow-effect” - caused by their fine banding. The green tones are caused by copper inclusions. Sometimes these inclusions are big enough to be seen with a microscope or with a strong lense. Besides the common fortification banding lakers can present the “water-level-banding”. Deformations in the banding can produce interesting patterns.
In the early days of collecting theses agates they were cut and polished (or even thumbled) - unless if they had a very fine natural pattern on the outside of the nodule. Today the collectors are prefering agates with a perfect shape and untreated pattern. The only treatment that is given to them is a bath in oil. This is enhancing the colors and is covering little cleavages.
Most of the specimen presented here on this page I could acquire in the year 2008 by visiting agate-collectors and on two shows - one was the “wonderfull world of agates”-show in Menasha. The other was the world-famous agate-show in Moose-Lake, Michigan, celebrated every year in juli. The masses of lake superior agates offered on these shows is unbelievable if you´re trying to collect lakers by yourself. The only remarkable stone I could find was a finelined greyish colored specimen.
You can get more detailed informations and pictures of fine Lake Superior agates here in the attached .pdf-file “The Other Lake Superior agate” of John D. Marshall. It is a really big file (11Mb !)- please consider the time for downloading.