Little Chicago nephrite, Marathon County, Wisconsin, USAi

Regional Level Types
Little Chicago nephrite	- not defined -
Marathon County	County
Wisconsin	State
USA	Country

Beginning in the late 1950s, attempts were made to promote a fine-grained metavolcanic rock as nephrite jade that was collected near a branch of the Little Rib River in Marathon County. An amateur collector and lapidarist, Guy Wilson found the material occurred as loose float blocks and, eventually, small outcrops. G.F. Hanson, state geologist at the time of the discovery, was sent several specimens. Using optical and X-ray diffraction techniques, he verified that the material was indeed mostly intergrown fibers of tremolite-ferroactinolite, hence could be defined as nephrite jade (Wisconsin Geological and Natural History Survey files). There was some debate as to the degree of translucency and color needed to technically qualify as “jade”. Wilson (1958) reports tumbling this material as well as making attractive rings and cabochons from it. He reports that the jewelry shows a “great many delightful patterns.” He described the material as follows: “Although most of it is opaque green, some has a bluish cast. Mottled and veined greens and blacks, greens and whites, some with yellow and yellowish patches, as well as solid greens occur. I have found one small brown piece.” (Wilson, 1958).

In 1971 two prospectors, George Friedrich and A. J. Werner were reported as finding a nephrite outcrop also in the Rib River area. This was again verified as nephrite by Wisconsin Geological and Natural History Survey geologists, as summarized in the December 1, 1971 issue of The Lapidary Reporter.

In 2014 a small pit was opened in bedrock exposing pale green nephrite - verified by XRD and optical techniques, and is being developed and marketed (2015) by Wisconsin Jade Inc.

Other Regions, Features and Areas containing this locality

References