Brochantite with Malachite after Azurite

specimen number:
1052743

location:
Tsumeb Mine, Otjikoto, Namibia

description:

Brilliant glistening needlelike green crystals of brochantite very rich across the front of matrix. Crystals of what were once azurite, these now replaced by green malachite are present as well. Wonderful example for the species from this locality, the specimen comes with an antique label as seen at the end of the video and dates to the very early 20th century. Note that the old label erroneously calls this atacamite.

The Tsumeb mine, located in the Oshikoto Region of northern Namibia, was a legendary underground mining operation internationally famous for its exceptionally complex polymetallic ore body and a vast array of secondary minerals. Geologically, the deposit was a steeply dipping, pipe-like structure that penetrated deep into the Neoproterozoic-age Otavi Group dolostones, formed as a massive paleokarst solution collapse breccia tube that acted as a major conduit for ascending hydrothermal fluids. These metalliferous fluids deposited rich primary sulfide ores containing copper, lead, zinc, silver, arsenic, and germanium, which later underwent extensive, deep-reaching groundwater oxidation across multiple distinct oxidation zones to produce unparalleled concentrations of rare arsenate and carbonate minerals like dioptase, azurite, mimetite, and cerussite. Historically, indigenous San and Damara people surface-mined and smelted the copper outcrops for centuries before European exploration led to the formation of the Otavi Minen- und Eisenbahn-Gesellschaft, which initiated formal industrial underground mining at the site in 1900. The mine operated almost continuously through the twentieth century under various corporate entities, including Newmont and Amax under the Tsumeb Corporation Limited banner, sinking deep shafts down to nearly fifteen hundred meters to extract millions of tons of high-grade base metal ore. Heavy commercial extraction sustained the local economy for nearly a century until structural financial difficulties, labor strikes, and the eventual depletion of economic deep-level ore reserves led to the permanent cessation of all mining operations at Tsumeb in 1996.

Arthur Kusche, operating out of Munich (Muenchen), Germany, during the early twentieth century, was a prominent mineral dealer who supplied high-quality regional and international specimens to notable European and global private collectors, academic institutions, and museums. Registered commercially as Arthur Kusche GmbH, his dealership functioned alongside other well-known contemporary Munich firms like Wilhelm Maucher and the Mineralogisches Institut, actively sourcing choice mineral specimens during the peak of central European geological exploration and mining activity. Geologically and historically, Kusche was instrumental in preserving and documenting the provenance of classic alpine, Scandinavian, and eastern European mineralized deposits, acquiring specialized pieces from legendary localities such as the silver mines of Freiberg, the polymetallic systems of Romania, and regional German pegmatites. Historical archives, museum catalogs, and acquisition logs from institutions like the Royal Scientific Society in Trondheim and the State Geological Museum of Lausanne confirm his commercial activities were highly vibrant throughout the 1910s and 1920s, showing that he routinely curated, cataloged, and sold pristine specimens embedded in calcite, quartz, and fluorite gangue matrices.

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