Mimetite

specimen number:
2102246

location:
Dry Gill, Caldbeck Fells, Cumbria, England, UK

description:
Classic British specimen with rounded lustrous crystals of mimetite, the groupings to 0.8 cm in diameter, across a quartz matrix. This is the variety known as campylite. In very good condition.

The Dry Gill Mine, located in a remote valley on the northern slopes of the Caldbeck Fells in Cumbria, England, is a legendary locality famous for its unique lead-arsenic mineralization. Geologically, the mine worked a north-south trending vein hosted within the Ordovician-aged Drygill Shales and volcanic rocks of the Borrowdale Volcanic Group, where the primary ores were subjected to intense alteration in a restricted chemical environment. This specific geochemistry led to the formation of the distinctive mimetite variety known as campylite, which occurs as barrel-shaped, curved crystals in shades of orange-red, brownish-red, or golden-yellow. Historically, the mine was worked intermittently during the 19th century, with the most significant periods of production occurring between 1846 and 1866 when it was exploited primarily for its lead content. While the mine was never a massive industrial producer compared to others in the district, it gained immense fame among mineralogists for the high quality and aesthetic appeal of its campylite specimens. Today, the site is a protected geological area and is recognized globally as the premier source for this specific and colorful habit of mimetite.

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