Oxide-zone minerals present the collector with many opportunities to acquire outstanding specimens with a wide range of bright colors, well-formed crystals, and varied chemistry. Weathered, leached, or hydrothermally altered areas above large deposits of the primary ores of copper, zinc, and lead have yielded great quantities of wonderful carbonates such as azurite, smithsonite, and cerussite. These zones are also known to produce rare secondary species with more complex chemistries and much more limited distribution. One such lead mineral from the latter category—leadhillite—is the subject of this issue's Connoisseur's Choice.
Robert J. Bowell is a geochemist with SRK Consulting in the United Kingdom as well as being an active commercial miner for minerals in Namibia. He works globally in the mining industry and is an avid collector of minerals, particularly those of the Otavi Mountain Land in Namibia.
Janet H. Clifford is a geologist by training though not by profession. An avid mineral collector for more than forty years, she enjoys field trips, exhibiting at mineral shows, volunteering at the Cleveland Museum of Natural History, and occasionally editing or writing for the hobby.