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Groutite
Lustrous black crystals of groutite throughout matrix with quartz. This is an excellent example for the species and in good condition.Groutite is a manganese oxide mineral that commonly forms in the oxidized zones of manganese rich iron deposits. It typically appears as dark brown to black prismatic crystals or massive material and is often associated with other manganese minerals such as pyrolusite and manganite. Specimens of groutite have been reported from the Rabbit Lake locality in Crow Wing County, Minnesota, an area later developed as part of the Cuyuna Iron Range. Iron mining near Rabbit Lake expanded during the 20th century after the discovery of ore beneath the lake, and the deposit produced iron ore along with various secondary minerals found in the altered rock.The previous label notes that this is possibly from the Pickens and Mather mine. I could not find any information on this, however there was a Pickands, Mather and Company who was a major mining and shipping company founded in 1883 in Cleveland that became heavily involved in iron mining around the Great Lakes. The firm developed and operated numerous iron mines and taconite operations in Minnesota, especially on the Mesabi Range, where surface mining produced iron ore for the steel industry.
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Known provenance
2026/04
Unknown Owner
$400.00—Species and Locality Wiki Pages
Collectors of Groutite from Minnesota
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