Germanite is a rare copper iron germanium sulfide mineral, Cu26Fe4Ge4S32. It was first discovered in 1922, and named for its germanium content. It is only a minor source of this important semiconductor element, which is mainly derived from the processing of the zinc sulfide mineral sphalerite. Germanite contains gallium, zinc, molybdenum, arsenic, and vanadium as impurities.
Azurite is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France. The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's Natural History under the Greek name kuanos (κυανός: "deep blue," root of English cyan) and the Latin name caeruleum. Since antiquity, azurite's exceptionally deep and clear blue has been associated with low-humidity desert and winter skies. The modern English name of the mineral reflects this association, since both azurite and azure are derived via Arabic from the Persian lazhward (لاژورد), an area known for its deposits of another deep-blue stone, lapis lazuli ("stone of azure").
Dioptase is an intense emerald-green to bluish-green copper cyclosilicate mineral. It is transparent to translucent. Its luster is vitreous to sub-adamantine. Its formula is Cu6Si6O18·6H2O (also reported as CuSiO2(OH)2). It has a hardness of 5, the same as tooth enamel. Its specific gravity is 3.28–3.35, and it has two perfect and one very good cleavage directions. Additionally, dioptase is very fragile, and specimens must be handled with great care. It is a trigonal mineral, forming 6-sided crystals that are terminated by rhombohedra.
Adamite is a zinc arsenate hydroxide mineral, Zn2AsO4OH. It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences. Pure adamite is colorless, but usually it possess yellow color due to Fe compounds admixture. Tints of green also occur and are connected with copper substitutions in the mineral structure. Olivenite is a copper arsenate that is isostructural with adamite and there is considerable substitution between zinc and copper resulting in an intermediate called cuproadamite. Zincolivenite is a recently discovered mineral being an intermediate mineral with formula CuZn(AsO4)(OH). Manganese, cobalt, and nickel also substitute in the structure. An analogous zinc phosphate, tarbuttite, is known.
Tsumeb is a city of 15,000 inhabitants and the largest town in Oshikoto region in northern Namibia. Tsumeb is known as the "gateway to the north" of Namibia. It is the closest town to the Etosha National Park. Tsumeb used to be the regional capital of Oshikoto until 2008 when Omuthiya was proclaimed a town and the new capital. The area around Tsumeb forms its own electoral constituency and has a population of 44,113. The town is the site of a deep mine that in its heyday was known as "TCL", but has since been renamed the Ongopolo Mine.
Tetrahedrite is a copper antimony sulfosalt mineral with formula: (Cu,Fe)
12Sb
4S
13. It is the antimony endmember of the continuous solid solution series with arsenic-bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common. Other elements also substitute in the structure, most notably iron and zinc, along with less common silver, mercury and lead. Bismuth also substitutes for the antimony site and bismuthian tetrahedrite or annivite is a recognized variety. The related, silver dominant, mineral species freibergite, although rare, is notable in that it can contain up to 18% silver.
Caledonite, whose name derives from Caledonia, the historical name of its place of discovery (Scotland), is a richly colored blue-green sulfate-carbonate mineral of lead and copper with an orthorhombic crystal structure. It is an uncommon mineral found in the oxidized zones of copper-lead deposits.
Native copper is an uncombined form of copper that occurs as a natural mineral. Copper is one of the few metallic elements to occur in native form, although it most commonly occurs in oxidized states and mixed with other elements. Native copper was an important ore of copper in historic times and was used by pre-historic peoples.
Kegelite is a complex silicate mineral with formula Pb8Al4Si8O20(SO4)2(CO3)4(OH)8.
Reinerite is a rare arsenite (arsenate(III)) mineral with chemical formula Zn3(AsO3)2. It crystallizes in the orthorhombic crystal system.
Plumbogummite is a rare secondary lead phosphate mineral, belonging to the alunite supergroup of minerals, crandallite subgroup. Some other members of this subgroup are:
Leightonite is a rare sulfate mineral with formula of K2Ca2Cu(SO4)4•2H2O.
Warikahnite is a rare zinc arsenate mineral of the triclinic crystal system with Hermann- Mauguin notation 1, belonging to the space group P1. It occurs in the Tsumeb mine in Namibia on corroded tennantite in the second oxidation zone under hydrothermal conditions in a dolomite-hosted polymetallic ore deposit. It is associated with adamite, stranskiite, koritnigite, claudetite, tsumcorite, and ludlockite. The origin of discovery was in a dolosmite ore formation within an oxidized hydrothermal zone, in the E9 pillar, 31st level of the Tsumeb Mine in Namibia, Southwest Africa. It has also been found at Lavrion, Greece and Plaka, Greece as microscopic white needles.
Tsumcorite is a rare hydrated lead arsenate mineral that was discovered in 1971, and reported by Geier, Kautz and Muller. It was named after the TSUMeb CORporation mine at Tsumeb, in Namibia, in recognition of the Corporation's support for mineralogical investigations of the orebody at its Mineral Research Laboratory.
Susannite is a lead sulfate carbonate hydroxide mineral. It has the formula Pb4SO4(CO3)2(OH)2. Susannite is the higher temperature phase of the two and forms above 80 °C when fluids oxidize the lead ore deposits. It is trimorphous with leadhillite and macphersonite.
Ianbruceite is a rare hydrated zinc arsenate with the formula [Zn2(OH)(H2O)(AsO4)](H2O)2; material from the Driggith mine has traces of cobalt. It was first discovered at Tsumeb, approved by the International Mineralogical Association as a new mineral species in 2011, reference IMA2011-49, and named for Ian Bruce, who founded "Crystal Classics" in the early 1990s, and was heavily involved in attempts to reopen the famous Tsumeb mine for specimen mining.
In 2013 new occurrences of ianbruceite were reported from the neighbouring Driggith and Potts Gill mines on High Pike in the Caldbeck Fells, Cumbria, England. Here the mineral is probably a post-mining product. Caldbeck Fells and Tsumeb are the only reported localities for ianbruceite to date (May 2013).
Hidalgoite, PbAl3(AsO4)(SO4)(OH)4, is a rare member of the beudantite group and is usually classified as part of the alunite family. It was named after the place where it was first discovered, the Zimapán mining district, Hidalgo, Mexico. At Hidalgo where it was initially discovered, it was found as dense white masses in alternating dikes of quartz latite and quartz monzonite alongside other secondary minerals such as sphalerite, arsenopyrite, cerussite and trace amounts of angelsite and alamosite, it was then rediscovered at other locations such as Australia where it occurs on oxidized shear zones above greywacke shales especially on the anticline prospects of the area, and on fine grained quartz-spessartine rocks in Broken Hill, Australia. Hidalgoite specimens are usually associated with copper minerals, clay minerals, iron oxides and polymetallic sulfides in occurrence.
The geology of Namibia encompasses rocks of Paleoproterozoic, Mesoproterozoic and Neoproterozoic and Paleozoic to Cenozoic age. About 46% of the countryʼs surface are bedrock exposure, while the remainder is covered by the young overburden sediments of the Kalahari and Namib deserts.
Arsendescloizite is a lead-zinc mineral, approved by the IMA in 1982. It is an arsenate analog of descloizite. Its first description was published in 1982.
Szenicsite is a copper hydroxy molybdate mineral, named after husband and wife Terry and Marissa Szenics, American mineral collectors who found the first specimens. When it was first discovered in Atacama, Chile, it was thought to be lindgrenite. The occurrence appeared in an isolated area, which was about one cubic meter in size. The mineral occurred in cavities of copper bearing powellite and matrix rich molybdenite. These cavities were filled with a material resembling clay. Outside of the zone the szenicsite crystals grew, copper levels seemed to decrease, and the mineralization changed to lindgrenite. Moving further from the zone, the minerals growing seemed to be lacking copper, and consisted of powellite blebs in the ore. Szenicsite was approved by the IMA in 1993.
