Azurite and Duftite on Quartz- Tsumeb mine, Otavi Highlands, Tsumeb, Namibia. by sysadmin | Jan 10, 2016 | Blog | 0 comments Azurite and Duftite on Quartz- Tsumeb mine, Otavi Highlands, Tsumeb, Namibia. 7.5 cm tall. Ex. Karl Sprich specimen. A rare combination from Tsumeb