Olivenite/TSUMEB MINE, TSUMEB, OSHIKOTO REGION, NAMIBIA

摘要

Hydrothermal copper deposits are dominated in their primary mineralogy by copper-bearing sulfide minerals such as chalcopyrite. When these deposits are exposed to oxygen and water under surface and near-surface conditions, as described in previous Connoisseur's Choice columns (e.g., Cook 2005), the sulfides become unstable and oxidize. Copper released from this reaction can form a plethora of "supergene" minerals, ranging from simple native copper and copper oxides to complex secondary minerals such as the highly collectible species olivenite (Berry 1951). As a continuation of our treatment of colorful secondary minerals, a specimen of olivenite from the world-famous Tsumeb mine in Namibia, where attempts at specimen mining have taken place in recent years (Cook 2002), has been selected for this issue.