The Tsumeb polymetallic carbonate-hosted replacement deposit in northern Namibia, although now closed, is a world-renowned deposit of unusual and complex minerals, particularly those of arsenic and germanium. Due to the presence of groundwater migrating through deep-seated faults that cross-cut the sulfide-bearing pipe two oxidation zones exist at depth that have led to the development of a complex mineralogical assemblage and paragenesis. Within the mineralized silica-rich pipe of the deposit approximately 337 minerals occur for which Tsumeb is the type locality for 72 of these minerals. Mineralisation is hosted in the Otavi Dolomite and the main ore body was a pipe that comprised massive peripheral ores, manto-style ores, disseminated and stringer ores. These ores were subjected to extensive oxidation not just from surficial weathering but also along deep-seated permeable faults that has developed complex secondary mineral assemblages at depth. Due to the karstic nature of the host dolomite there has been considerable water flow through the deposit and during operations into the mine workings, even during early mining, often with different water chemistry and this is reflected in the mineral assemblages formed. The deposit was mined from 1897 to 1996 and for a time was the largest lead producer in Africa. The complex and renowned mineralogy has resulted in thousands of mineral specimens being preserved from the mining operations. Important collections housed in the Geological Survey of Namibia include specimens collected by Hans Schneiderhöhn [1887-1962], professor of Mineralogy, University of Freiburg im Breisgau, Germany, who studied the deposit in the early twentieth century and whose contribution is recognized by the mineral Schneiderhöhnite, a mixed valency iron arsenite; and that of Gerhard Söhnge [1913-2006], who was chief geologist of Tsumeb corporation from 1950- 1968 and whose contribution is recognized by the mineral Söhngeite, the only known gallium-oxide mineral. In addition to these the museum houses the specimen collection of the last mine manager at Tsumeb, Tony De Beer that comprises excellent display quality material of the more common minerals from Tsumeb. Cataloguing and amalgamation of these collections into the main GSN collection is currently being undertaken (2015-ongoing). During this exercise a number of species have been identified that were previously unknown or poorly described from Tsumeb along with variations of known minerals that may prove to be new minerals. These minerals include: Quartz variety Amethyst; Sb-Arsenbrackebuschite; Arthurite; Argyrodite; Arsenocrandallite; Cobalt-tsumcorite; Freedite; Kintoreite; Lindackerite; Marcasite; Matlockite; Phillipsbornite; Skorpionite; Surite, Zn-rich Surite Vésigniéite and Wroewolfeite. In addition Arsenbrackebuschite was found to be the major mineral on several specimens originally labelled as being Tsumcorite and may be more widespread than originally described and more detailed description of associations are included for Arsenbrackebuschite, Arseniosiderite, Arsenogoyazite, Arsenohopeite, Covellite, Pharmacosiderite, and Yvonite. Detailed descriptions of these minerals are included here and discussed in the context of the established paragenesis and implications for understanding the stability and formation of the different mineral assemblages at Tsumeb. Keywords: Tsumeb Mine, Mineralogy, Namibia.