Conichalcite
specimen number:
2072306
location:
Gold Hill Mine, Tooele Co., Utah, USA
description: The Gold Hill Mine, located in the Clifton District of the Deep Creek Mountains in Tooele County, Utah, is situated within a geologically complex region characterized by a large Jurassic quartz monzonite stock that intruded into Paleozoic sedimentary rocks. This intrusion created extensive skarn deposits and hydrothermal vein systems rich in arsenic, copper, and lead, which underwent significant secondary oxidation to produce a vast array of rare minerals. The locality is world-renowned for its exceptional specimens of conichalcite, a calcium copper arsenate hydroxide, which typically occurs as vibrant, apple-green to grass-green botryoidal crusts and velvety aggregates coating the matrix. Historically, mining and quarrying in the Gold Hill area began in the late 1850s, with periods of intense activity during World War I and World War II to extract arsenic for agricultural use and tungsten for the war effort. While major commercial operations for industrial metals largely ceased by the mid-20th century, the site has remained a significant destination for mineralogists and collectors through 2026 due to its status as a premier locality for secondary arsenate minerals.
Green botryoidal crystallized conichalcite very rich across the front of matrix. Nice for the species and locality. In good condition.
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