Beryl

specimen number:
2133345

location:
Byrud Mines, Minnesund, Eidsvoll, Akershus, Norway

description:
Green prismatic crystalline beryl, the variety known as emerald, to 0.5 cm in length embedded within matrix. Interesting locality example.

The Byrud mines, located on the shores of Lake Mjosa near Minnesund in the Eidsvoll municipality of southern Norway, comprise a historic underground operation famous for being the only commercial source of gem-quality emeralds ever worked in Scandinavia. Geologically, the deposit sits within a rift structure of Permian age at the northeastern border of the Oslo Rift Valley, where flat-lying maenaite and syenitic pegmatite sills intruded into Cambrian-aged alum shales. Hydrothermal fluids circulating through these intrusions leached essential chromium and vanadium from the surrounding black shales, precipitating small but highly prized emerald crystals along the contact zones within the pegmatite matrix. The presence of green beryl crystals at the site was initially noted by collectors and mineralogists during the late 1860s and 1870s, but structured commercial extraction did not begin until April 1899, when the property was purchased by British interests. Operating primarily as the Norwegian and General Exploration Company, Limited, the venture employed up to thirty miners during its peak years, even exhibiting a selection of its cut gems at the Paris World Exposition in 1900. However, due to a steep decline in productivity and a high percentage of fractured or heavily included crystals, organized industrial mining was permanently abandoned in 1909, though the old gallery workings remain open today as a popular tourist attraction where hobbyist collectors are permitted to search the waste dumps for remaining specimens.

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