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Minerals of the
Kaokoveld District
Kunene Region, Namibia
Robert J. Bowell1
Olga Ermolina2
Wim van der Plas3
Jesper van Us3
Marius Steiner4
The Kaokoveld copper district is currently an excellent source of fine
minerals, particularly dioptase, wulfenite, malachite, the world’s best
shattuckite, and other secondary copper and lead species.
Ongoing exploration and mining activity in the area will likely continue
to provide specimens for some time to come.
INTRODUCTION
Namibia has long been a major source of collector-quality min-
eral specimens, especially the secondary base metal minerals from
famous localities like the Tsumeb, Kombat and Otavi mines, and
more recently from the Skorpion mine. Over the last two decades
there has been a near continuous production of excellent dioptase
and, more recently, cerussite, cuprite, malachite, shattuckite and
wulfenite specimens from northwestern Namibia in the Kaokoveld
district of the remote Kunene region. Associated minerals include
rare secondary bismuth species such as bismuth-rich mottramite,
beyerite and bismutite.
Dioptase, particularly well known from Tsumeb and Guchab
(Bezing et al., 2007), has also been found in the Kaokoveld region
as world-class specimens, but unlike Tsumeb and Guchab these
specimens come from relatively shallow workings and have largely
1 SRK Consulting, Churchill House, Churchill Way, Cardiff
CF103BX, Wales
2 Institute of Mineralogy, Miass, Russia
3 Kaokoland Mining and Exploration Co., Swakopmund, Namibia
4 Camp Aussicht, Kunene, Namibia
been mined by small groups of artisanal miners and/or collectors
specifically for specimens, rather than metal content. Consequently
the mining by hand has led to greater preservation of material.
In the last five to ten years these workings have also become
a source of excellent shattuckite, barite, anglesite and wulfenite.
The main sources are the Omaue mine, the Okandawasi, Onderra,
Ongankwa and Kandesei pits and the Van der Plas and Otuani mines.
These mines have been described previously, primarily in the Ger-
man literature (Palfi, 2005; Von Bezing et al., 2007; Niedermayr
et al., 2008; Schnaitmann and Jahn, 2010; Brandstätter, 2012). The
two senior authors have worked on copper exploration programs
in the area since 2008; the other authors have been involved in
dioptase mining in the area for the last 20 years. This has allowed
us the opportunity to visit the workings and study the geology of
this fascinating area.
SITE ACCESS
The Kaokoveld mining district is located in the Kunene region
of northwestern Namibia. The main mining areas, located approxi-
mately 10 km from the main road between Opuwo and Sesfontein,
are connected to the capital city of Windhoek by a paved two-lane
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The Mineralogical Record, volume 44, July–August, 2013
highway. There are two main turnoffs to the site: approximately 55
km from the town of Sesfontein and 80 km south of Opuwo. The
Omaue mine is conveniently situated adjacent to Camp Aussicht.
In total, reaching the turnoff road to the mining area at the northern
access point takes about an hour, after covering a distance of 40 km.
The South turnoff to the mine areas is about 20 km long but the
quality of the road is very poor and takes a similar period of time.
The road leads to the South part of the mining area via a camping
area where a rest camp is located. The developed road network is
of quite poor quality within the main mining area going all the way
from south to the north of the area. Much of the driving access is
along dry river beds that are not passable in the wet season.
Namibia has a temperate and subtropical climate character-
ized by hot and dry conditions with little rainfall along the coast.
Temperatures are moderated by the cold Benguela current while
Figure 1. Location map showing the location
of the Kaokoveld mines between Opuwo and
Sesfontein in the Kunene Region, northwestern
Namibia. The locations of some other well known
mining sites are marked as well.
Figure 2. Location of the various mines and
mineral occurrences in the Kaokoveld area.
The Mineralogical Record, volume 44, July–August, 2013
2
periods of winter drought alternate with excessive summer rainfall
between November and April, with the interior experiencing slightly
higher rainfall. Average annual precipitation in the capital city of
Windhoek is 360 mm (14 inches) and the average temperature
range from 43° to 68°F in July and 63° to 84°F in January. These
average temperatures are typical of the central plateau which has
an average elevation of approximately 1,600 meters.
The lower average elevation of the mining area results in some-
what higher average temperatures. The location in the northern part
of Namibia means that seasonal rainfall begins slightly earlier but
is of roughly the same magnitude as that recorded for Windhoek.
Consequently all specimen mining stops by early December and
in general is not resumed until mid-April.
GEOLOGICAL SETTING
The Damara Orogen in Namibia consists of a 400-km-wide
northeast-trending intracontinental arm and a north-south-trending
coastal arm. The mining area is situated in the coastal arm, formed
during late Proterozoic to Early Palaeozoic time in a rifting envi-
ronment (Ajagbe, 1999a,b; Miller, 2008). The north-northwestern
rift underwent multiple phases of subsidence, but ophiolites and
ultrabasic rocks are not present in the area. The earliest unit in the
rift is the Nosib Group which, in the mining area, is dominated
by coarse clastic sedimentary rocks. The quartzite found in the
northwestern part of the mining area is a part of this formation.
The sedimentary rocks hosting all of the mineral occurrences
in the area were deposited in intercontinental rift basins in which
Figure 4. Mineralization exposed in
the Okohongo pit, developed at the
base of a copper-silicate-rich breccia
2 meters thick. Robert Bowell photo,
October 2011.
Figure 3. The Otuani open pit and box
cut, in operation since 2006. The workings
exploit a horizon ofbornite and chalcocite
ore. Robert Bowell photo, October 2010.
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The Mineralogical Record, volume 44, July–August, 2013
carbonate rocks of the Otavi Group dominate and overlie the
Nosib terrigenous sediments. The Otavi Group is divided into
three Subgroups and one formation: a lower Ombombo Subgroup,
the Chuos formation, the middle Abenab Subgroup and an upper
Tsumeb Subgroup.
The Obombo Subgroup consists of intercalated limestones,
slates, shales and dolomites. These rocks host most of the stratiform
deposits of disseminated and partially oxidized pyrite, chalcocite,
galena and bornite. Contemporaneous vein and stockwork miner-
alization (quartz and quartz-chlorite-carbonate veins and stringers
with copper and lead sulfides) occurs in both the Obombo and
Abenab carbonate rocks. The lower part of the Obombo Subgroup,
also known as the Lower Omao sequence, is divided into four main
stratigraphic units; the Lower Omao hosts all known copper occur-
rences in the mining district.
The Chuos Formation, up to 150 meters thick, lies conformably
above the Ombombo rocks in the western and eastern parts of the
mining area on the limb of the anticline. The unit is composed of
poorly sorted conglomerate and iron-bearing quartzite.
Sitting above the Chuos Formation in the mining area are carbon-
ate rocks of the Abenab Subgroup. This unit is composed of massive
dolomite and reef stromatolite limestone with minor intercalated
argillaceous shales near the top of the sequence. North of the min-
ing some mineralized, copper-rich breccias are hosted within this
unit, presumably a reflection of the competency of the unit and the
role of the carbonates in buffering mineralizing fluids. Some karst
features occur in the mining area within this unit.
Metamorphism in the area equates to the prehnite-pumpellyite
facies based on the calcite-dolomite-quartz assemblage, the absence
Figure 5. Massive copper-lead-barite mineralization
in the Okandawasi pit (sometimes referred to as
Kandesi pit, the Kaokoveld mine, or the Old German
mine) is situated at the top of Okomunwe Hill and is
the largest excavation for mineral specimens in the
area. Robert Bowell photo, July 2011.
Figure 6. Folded chalcocite-galena-barite
mineralization in the Okandawasi (Kandesi)
pit Robert Bowell photo, July 2011.
The Mineralogical Record, volume 44, July–August, 2013
4
of tremolite and talc and the development of muscovite and chlorite
in the more argillaceous units, possibly indicating conditions close
to the boundary with lower greenschist facies.
The Weathering profile in the mining area is not particularly well
developed due to physical erosion in the steeply undulating terrain
of the mining area. Consequently regolith profiles consist of poorly
developed shallow calcareous soils extending no more than 50 cm
on slopes with a very thin or non-existent organic soil and leaf
litter cover. Current drainage flows on shallower slopes and along
valley floors have deposited alluvial sediments to 2 meters or more
in depth. In places, solution weathering of the carbonate hosts rocks
and migration of carbonate in groundwater has partially cemented
these clastic alluvials to form calcrete or caliche deposits in which
the clastic fragments are cemented by calcite and clay minerals.
Smectite-rich clay patches do occur and locally form dambo soil
horizons with associated springs and shallow perched aquifers.
The rocks of the region are intensively folded. Within the central
part of the anticline the folding shows the disharmonic character-
istics with both secondary and tertiary level folding. The dip of
the layers varies from 30° or 40° to vertical. The folds are usually
inclined with the western dipping of the axis plane at 30° to 40°
(Miller, 2008). Tectonic features include (usually overthrust) faults of
west-southwest orientation, accompanied by intensive hydrothermal
secondary alteration and mineralization. The north-south-orientated
faults within the anticline area usually correspond to the zones of
argillization, silicification and base metal mineralization. In the
transition zones between the central anticline to west of the EPL
and the east syncline significant thrusting can be observed that
offsets the regional geological fabric. The rocks in the area of the
thrust faults are intensively mineralized by hematite.
Three principal mineral assemblages have been mapped and
sampled in the mining area: (1) Stratiform disseminated copper
sulfide with associated pyrite and galena secondary minerals of cop-
per, lead and iron; (2) Stockwork mineralization containing quartz
veins hosting lenticular or pocket-like copper sulfides with associ-
ated galena and secondary minerals; and (3) Fault-related quartz
veining with lenticular concentrations and stringers of chalcocite,
galena and associated secondary minerals.
The primary ore at Okatumba consists mainly of chalcocite
with minor bornite, galena and pyrite. Tetrahedrite and sphalerite
are present but rare. Silver appears restricted to trace amounts
in galena. The main gangue minerals are quartz, chlorite, calcite
and barite. All three types or ore assemblages have been heavily
oxidized in the mining area, especially in the zones of stockwork
and fault-controlled mineralization. The oxidation zone can reach a
depth of 50 meters or more (as revealed by core drilling). Numerous
copper-bearing secondary minerals occur in the weathered zones.
Oxidation and weathering of the primary ore has led to supergene
enrichment of copper at the base of oxidation zone, but not as the
typically expected mineral assemblage of cuprite and native copper
but rather as copper silicate minerals. Most likely this occurred dur-
ing the Quaternary period when the area was undergoing tectonic
uplift with dry climate with short rainfalls.
DESCRIPTION OF THE PROSPECTS
The copper-rich mineralization in the Kunene Copper Belt has
been actively explored for over 50 years. Despite this no large depos-
its have ever been located. Mineral exploration is still being carried
out in the area by Teck Cominco, INV Metals, Kaokoland Mining
and Exploration Company and Siberia Metal Traders as well as a
number of independent prospectors. The majority of the specimen
mining is being undertaken by members of the local Herero tribe.
Only one organized mechanical mining operation, by Kaokoland
Mining and Exploration, is currently active, at Okomunwe, and this
produces on the order of 400 tonnes per month of copper concentrate
from a rich chalcocite and malachite ore typically grading 15% to
25% copper. There is also some production from other Kaokoveld
Mining Exploration operations such as Okandawasi which is pro-
cessed at the Otuani site.
One of the biggest challenges facing collectors of Kaokoveld cop-
per minerals is keeping track of the names of the various prospects
in the area (Lowmayr et al., 2008; Niedermayr et al., 2008; Bowell
and Cook, 2009; Schnaitmann and Jahn, 2010). The problem was
exacerbated by early exploration reports which applied some names
to more than one prospect. For example, Onderra, the locality for
excellent Wulfenite crystals, is situated approximately 10 km south
Figure 7. The
Okandawasi (Kandesi)
pit. Robert Bowell
photo, October 2010.
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The Mineralogical Record, volume 44, July–August, 2013
of the Otuani mine but is also the name for two exploration licenses
(Onderra East and West) located further to the south. In addition
some pits have more than one name, bestowed by different opera-
tors or obfuscated by the crystal sellers in order to keep a location
secret. The Okandawasi pit is variously known as Kandesi (also used
for a pit to the south of Omaue mine) or the Old German mine. In
addition the site has been known as the Kaokoveld mine after the
name of the current operators, Kaokoland Mining and Exploration,
and it has been reported that the locality name Otjikotu has been
cited by American dealers for minerals coming from both of the
Kandesei pits (Niedermayr et al., 2008). Our preferred name in this
article is the name used by the current mine owners or operators,
and it is recommended that this name be adopted. Table 2 provides a
summary of these names and the listed mineralogy for each locality.
The mineral occurrences in the area are discussed here, from north
to south, and are shown in Figure 1.
Mineral excavations vary considerably from large pits at Otuani
and Okandawasi to small trenches in the vicinity of Okohongo.
Some attempts have been made to provide a more formal, and
safer, method of mining for specimens but so far little progress has
been made except on the properties of the Kaokoland Mining and
Exploration Company and at the Omaue mine. The known mineral
localities are as follows.
Figure 9. Copper mineralization in the bottom
of the Christoff mine pit, situated close to the
Okandawasi pit. In 2007 the Christoff mine
produced an exceptional haul of dioptase
crystals. Robert Bowell photo, May 2010.
Figure 8. View looking towards the
anomaly G workings, theonly occurrence
of conichalcite in the Kaokoveld area.
Robert Bowell photo, March 2009.
The Mineralogical Record, volume 44, July–August, 2013
6
Okohongo
The Okohongo locality consists of a small pit developed at the
base of a copper-silicate-rich breccia 2-meters wide. Minor work has
taken place there intermittently over two decades, but no exceptional
mineral finds have been recorded.
Otuani
The Otuani locality is a large open pit and box cut that has been
in operation since 2006. The workings exploit bornite and chalco-
cite ore with a copper content of up to 25%, exposed over 4-meter
area. Above the primary ore is a zone of malachite, dioptase and
chrysocolla.
Onderra
The small Onderra pit was initially developed in 2005 on lead-
copper mineralization in the limestone country rock. Over time the
pit has been extended by local Herero workers. The small subsidiary
pits in this area have yielded fine wulfenite specimens.
Okandawasi
The Okandawasi pit (sometimes referred to as Kandesi pit, the
Kaokoveld mine, or the Old German mine) is situated at the top of
Okomunwe Hill and is the largest excavation for mineral specimens
in the area. More than 20 minerals have been reported from this pit.
The workings exploit pods rich in chalcocite and copper silicate
mineralization exposed in the apex of folds within the Obombo and
Abenab units. Okandawasi has been the main source of fine dioptase
and shattuckite specimens over the last five to eight years and is
currently being expanded along strike and to the east; additional
pockets continue to be found.
Christoff mine
Situated close to the Okandawasi pit and also mined by the
Kaokoland Mining and Exploration Company, the Christoff mine
pit has also (like the Okandawasi pit) been referred to as the Old
German mine. In 2007 the locality produced an exceptional haul of
dioptase crystals and has also yielded some fine cerussite, cuprite
and mottramite specimens as well.
Van Der Plas mine
The Van Der Plas mine, also located close to the Okandawasi
pit, began in 2009 to produce excellent cerussite twin crystals up to
4 cm in length as well crystal groups. The mineralization is an exten-
sion of the mineralized zones at Okandawasi and shows an almost
identical mineral assemblage. Some of the wulfenite crystals from
this locality reach up to 6 cm in size, but they are commonly coated
by a mixture of clay, manganese oxides and silica that is almost
impossible to remove without damaging the wulfenite surface.
Omaue Mine
The Omaue mine at Camp Aussicht has been the premier producer
of dioptase from Kaokoveld region for over 20 years and has been
operated and developed by Marius Stiener. Although the original
locality is now depleted, prospecting on site has identified new areas
of mineralization in the same geological host rock and Steiner hopes
that these will also yield dioptase crystals. On occasion this site has
produced excellent yellow anglesite and barite as well.
Okatumba
The Okatumba mine lies approximately halfway between Opuwo
and Sesfontein, about 500 meters from the main road close to
the village of Okatumba. The location has been mined by a local
prospector, Jaco Smith from Usakos, with the help of local miners,
and they have recovered some excellent wulfenite specimens, the
best of which are in Jaco’s collection.
Otjozongombe (Kandesi)
Further to the south of Omaue is the Otjozongombe prospect, also
referred to as the Kandesi prospect by some of the local miners.
This locality exploits dioptase-rich mineralization almost identical
to that found at Okandawasi.
Okapanda (Otjhowe)
A small excavation called the Okapanda pit is located on the side
of Okomunwe Hill to the south of the main mining area there. This
may be the same as the Otjhowe prospect described by Schnaitmann
and Jahn (2010); Otjhowe is the name of a local farm. Workings
in this area have been intermittently active and in the last two or
three years have yielded some excellent dioptase.
Okarvizo
The large Okarvizo pit developed to the south-southwest of Oko-
munwe Hill exploits a chrysocolla-rich breccia containing pockets
of small, in some cases doubly terminated dioptase crystals. The
Figure 10. Entrance
to the Omaue mine.
Note the chrysocolla-
rich vein almost a
meter thick to the
left of the portal.
Robert Bowell photo,
September 2009.
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The Mineralogical Record, volume 44, July–August, 2013
dioptase in this breccia is occasionally coated by mottramite and
vanadinite.
Omatapati
The small Omatapati open pit is said to have produced lapidary-
grade Chrysocolla and good dioptase.
Okakuyu
The Okakuyu workings are the southernmost locality known for
secondary copper mineralization. On our last visit we saw chryso-
colla, planchéite, malachite and dioptase on the dumps.
MINERALS
Anglesite PbSO4
Anglesite is a common secondary mineral in the Kaokoveld
deposits. It has been found as colorless, gray or yellow crystals
and is generally associated with calcite, cerussite, chrysocolla,
dioptase, hematite, malachite and quartz. The best material was
mined between 1998 to 2002 from the Omaue mine, where ter-
minated anglesite crystals to 2 cm were recovered. The only other
notable anglesite specimens from the area are colorless, terminated
crystals to 2 mm on galena recovered in 2011 from an exploration
trench close to Otuani.
Apachite Cu9Si10O29?11H2O
Greenish blue botryoidal crusts of fine needles of apachite have
been found on chrysocolla from the Okandawasi pit (identified at the
University of Miass in material collected in 2008). The individual
needles are approximately 0.1 to 0.3 mm in size.
Azurite Cu3
2+(CO3)2(OH)2
Azurite is surprisingly rare in the Kaokoveld district and gener-
ally only in the form of malachite pseudomorphs after azurite up
to 1.5 cm. Azurite has been collected as rough crystal fragments
up to 4 cm in size from the Van Der Plas mine and up to 1.5 cm
from Okandawasi pit; historically it has also been reported from
the Omaue mine.
Barite BaSO4
Barite is a common mineral throughout the Kaokoveld district.
As with anglesite it forms crystals that vary from colorless to gray
to yellow, in habits that can easily be mistaken for anglesite. Excel-
lent crystals of barite were recovered in 2011 from the Okomunwe
area and from Okapanda as well.
Transparent lemon-yellow blades up to 1.5 cm on white calcite
have been reported from Onderra (Schnaitmann and Jahn, 2010).
Similar material has been collected from the Christoff mine and
from the Van Der Plas mine. At the latter occurrence barite is asso-
ciated with malachite and shattuckite as well. An unusual fibrous
form of barite, mostly to white to yellow in color, has been found
at Okatumba (Niedermayr et al., 2008).
Beyerite Ca(BiO2)(CO3)2
Beyerite was first identified in material from the Kandesi pit (Nie-
dermayr et al., 2008) and has since been found at Okandawasi and
Figure 12. Cerussite, 7.1 cm, from Kaokoveld.
Jürgen Tron specimen; Jeff Scovil photo.
Figure 11. Cerussite V-twin, X cm, from
Kaokoveld. Marshall Sussman specimen;
Wendell Wilson photo.
The Mineralogical Record, volume 44, July–August, 2013
8
at the Christoff mine. It occurs as millimeter-size rosettes, spherules
and radial-fibers with adamantine luster associated with mottramite
(sometimes Bi-rich), shattuckite, malachite, calcite and dolomite.
Bismutite (BiO)2CO3
Bismutite was reported by Schnaitmann and Jahn (2010) from
Okatumba, where it occurs as yellow, platy, botryoidal crusts with
adamantine luster associated with malachite and wulfenite. It is
almost indistinguishable from beyerite.
Bornite Cu5FeS4
Bornite occurs as scattered disseminations in carbonate rocks.
It commonly contains thin lamellae of chalcopyrite and forms
intergrowths with chalcocite. Microprobe analyses have shown that
bornite contains trace amounts of silver. A recent bornite-rich zone
uncovered in August 2012 had yielded some of the first crystals
of bornite from the Kaokoveld area. The zone contains ore grades
typically of 10–15% copper with silver up to 420 mg/kg (or 13.5
ounces per ton).
Calcite CaCO3
Calcite is a common mineral throughout all of the known work-
ings in the Kaokoveld district. Large rhombohedral crystals, many
showing an attractive mosaic of hematite and manganese oxide
inclusions, are known from the Okomunwe, Okandawasi and Van
Der Plas mines. At Onderra, calcite occurs as transparent to milky
white crystals associated with dioptase that is very reminiscent of
classic Tsumeb calcite-dioptase specimens.
Figure 13. Dioptase crystals on matrix, 12.3 cm, from
Kaokoveld. Rob Lavinsky (The Arkenstone) specimen,
now in the Pinnacle collection; Joe Budd photo.
Figure 14. Gemmy dioptase crystal, 1.8 cm, from Kaokoveld.
Rob Lavinsky (The Arkenstone) specimen; Jeff Scovil photo.
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The Mineralogical Record, volume 44, July–August, 2013
Cerussite PbCO3
Good cerussite crystals have only been noted relatively recently
from the Kaokoveld district. Exceptional V-twin crystals up to 3 cm
have been recovered from the Van Der Plas mine. Prismatic crystals
up to 1 cm with metallic luster have been recovered from the same
locality and from the Christoff mine. At Okatumba similar cerus-
site crystal combinations have been collected in association with
massive shattuckite and malachite (Schnaitmann and Jahn, 2010).
Chalcocite Cu2S
Chalcocite is the main ore mineral in the district but is rarely
found as terminated or well-defined crystals. Massive chalcocite
does occur, particularly in the apex of folds and commonly associ-
ated with malachite and other secondary copper minerals, although
some of what has been called chalcocite may instead be djurleite
(see below). At Okandawasi masses of chalcocite up to 30 cm have
been found along the axis of tight isoclinal folds on the limb of a
large anticline in Abenab limestone.
Chenevixite Cu2
2+Fe2
3+(AsO4)2(OH)4?H2O
Chenevixite has been reported from the Omaue mine by Palfi
(2005). Arsenate minerals in general are scarce in the Kaokoveld
mineralized zones, in stark contrast to Tsumeb.
Chlorargyrite AgCl
Pale, waxy, yellowish green masses of chlorargyrite to 1 mm
associated with cerussite, namibite and beyerite have been found
at the Okandawasi pit. Although chlorargyrite has not been at any
Figure 15. Dioptase crystal cluster, 4.7 cm,
from Kaokoveld. Marshall Sussman
specimen; Jeff Scovil photo.
Figure 16. Opaque dioptase crystal on matrix,
4.6 cm, from Kaokoveld. Irv Brown specimen;
Jeff Scovil photo.
The Mineralogical Record, volume 44, July–August, 2013
10
Figure 17. Dioptase crystal
fan, X cm, from Kaokoveld.
Marshall Sussman specimen;
Wendell Wilson photo.
Figure 18. Dioptase crystal cluster, X cm,
from Kaokoveld. Marshall Sussman
specimen; Wendell Wilson photo.
Figure 19. Dioptase crystals on
quartz, X cm, from Kaokoveld.
Marshall Sussman specimen;
Wendell Wilson photo.
11
The Mineralogical Record, volume 44, July–August, 2013
other Kaokoveld occurrences, geochemical analysis of oxide ores
periodically show silver. The highest silver content, up to 270 mg/kg,
is from Otuani, most likely in the form of microscopic chlorargyrite
inclusions or in relict argentiferous galena.
Chrysocolla (Cu,Al)2H2Si2O5(OH)4?nH2O
Chrysocolla is common to the entire specimen digging areas in
the Kaokoveld district. Lapidary-grade chrysocolla has been mined
for two decades in large volume and sold as Lapidary rough. More
recently, because of rising copper prices, hand-sorted chrysocolla ore
has been shipped to the Tsumeb smelter for commercial processing.
In general, chrysocolla occurs as massive, occasionally botryoidal
material and generally covers or replaces the other copper silicate
minerals except for a second generation of dioptase.
Conichalcite CaCu2+(AsO4)(OH)
The rare arsenate conichalcite has only been observed at one place
located in the exploration license 3799 area near the Kandesi pit at
what is called “anomaly G.” There in shallow workings it occurs
with chrysocolla, mimetite, malachite, planchéite and shattuckite.
It forms pale green, sub-vitreous, botryoidal to reniform crusts.
Copper Cu
Native copper occurs as rare disseminations in carbonate rocks. The
particle sizes range from visible (about 1 mm) to microscopic (0.01
mm). In some areas native copper has been replaced by cuprite which
forms fringes and is often itself replaced by malachite (see below).
Cuprite Cu+
2O
Cuprite is widespread although never abundant in the Keokoveld
district, and to date has been found at the Otuani, Okandawasi,
Christoff, Van Der Plas and Kandesi mines. It typically occurs as
massive material associated with chrysocolla and malachite but
cubes and octahedral crystals up to a few millimeters in size have
also been collected.
Dioptase Cu6Si6O18?6H2O
Dioptase is the most attractive and desirable of all the minerals
found in the Kaokoveld district. It is generally restricted to and is
best developed in dolomite host rocks. In comparison to dioptase
from Tsumeb and elsewhere it has a slight bluish tint to the typical
emerald-green color and forms thinner, more elongated crystals.
The most common associations are quartz, malachite, planchéite
and shattuckite. At least two generations of dioptase exist in the
district. The first is widespread in most of the workings and typically
occurs as small crystals no more than 1 cm, with most being less
than 5 mm. Where dioptase is preserved it is commonly coated by
quartz and, more rarely, by hemimorphite giving a “sugar-coated”
appearance; these specimens are particularly common at Okanda-
wasi, Kandesi and Okatumba.
At Onderra small dioptase crystals to 5 mm are associated with
wulfenite in white quartz. In some cases first-generation dioptase
is associated with a kaolinite-like matrix containing spherical
shattuckite aggregates and minor amounts of calcite. Much of the
dioptase in this occurrence is unfortunately badly preserved.
At many of the localities a second generation of dioptase on
chrysocolla appears to be the last copper silicate to have precipi-
tated. This later generation of dioptase includes some of the finest
crystals that have come in recent years from the Christoff, Kandesi,
Okandawasi, Okarvizo and Omaue locations, as individual crystals
to 9 cm. More typically they range from a few millimeters to
3 cm in size. Doubly terminated crystals of dioptase up to 3 cm in
size have been collected from these localities. One of the finest,
from Otjihowe, is a 1.5-cm, doubly terminated crystal on calcite
(Schnaitmann and Jahn, 2010).
Figure 20. Dioptase crystal
group with shattuckite, X cm,
from Kaokoveld. Marshall
Sussman specimen; Wendell
Wilson photo.
The Mineralogical Record, volume 44, July–August, 2013
12
At Omaue, second-generation dioptase is typically associated
with honey-yellow barite, chrysocolla, malachite, planchéite, shat-
tuckite and more rarely anglesite and wulfenite. At the Christoff
and Okandawasi mines second-generation dioptase is often found
partially coated by mottramite (some of it bismuth-rich) and bey-
erite. At the Kandesi mine highly lustrous crystals up to 2.5 cm in
size have been found on a matrix of bright yellow, glassy lustered
calcite rhombohedrons described by Schnaitmann and Jahn (2010).
Djurleite Cu31S16
A thin-section study conducted at the Institute of Mineralogy
(Miass) identified much of what has been considered in the field
to be massive “chalcocite” is in fact djurleite. This is particularly
true of the sulfide-rich veins in the Okandawasi pitSeltene, massive,
gelegentlich angelaufene Klumpen bis 3 cm Größe in massivem
Shat-tuckit, Malachit und Quarz haben sich als Djurleit erwiesen
(Analyse G. Niedermayr). Djurleite is associated with shattuckite,
malachite and quartz.
Dolomite CaMg(CO3)2
Although much of rock of the Ombombo and Tsumeb subgroups
is primarily dolomite, relatively little dolomite in collectable crystal
form has been found in the workings. Calcite locally can contain a
few percent magnesium. However, dolomite is generally restricted
to forming small (less than 5 mm), pearly crystals, generally as a
late-stage precipitate on the copper silicates.
Galena PbS
Galena is common in many of the deeper workings and even in
some veins at some surface. It generally occurs as massive to cubic
galena, often partly corroded. It is associated with calcite, cerussite,
chalcocite, leadhillite, mimetite, mottramite and quartz.
Goethite Fe3+O(OH)
Goethite is widespread in the district, generally as earthy aggre-
gates but also as inclusions of fine black needles to 2 mm in quartz,
calcite and barite.
Hematite Fe2O3
Hematite-bearing ironstones occur in the Abenab subgroup
throughout the field district. Within areas of copper mineralization
it has been reported as crystals at Okatumba, where it occurs as
single crystals and masses up to 4 cm in size associated with shat-
tuckite, beyerite, bismutite and Bi-rich mottramite (Schnaitmann
and Jahn, 2010).
Figure 21. Malachite (non-pseudomorphous),
X cm, from Kaokoveld. Marshall Sussman
specimen; Wendell Wilson photo.
Figure 22. Malachite pseudomorphs
after cuprite, 3.6 cm, from Kaokoveld.
Luis Burillo specimen; Jeff Scovil photo.
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The Mineralogical Record, volume 44, July–August, 2013
Hemimorphite Zn4Si2O7(OH)2?H2O
Hemimorphite has only been found as partial to complete coat-
ings on dioptase, malachite and shattuckite in specimens from
Okandawasi, Kandesi and Okatumba.
Iodargyrite AgI
Iodargyrite is listed as coming from the Kandesi mine by Nie-
dermayr et al. (2008)
Lanarkite Pb2O(SO4)
Lanarkite has been reported from the Van der Plas mine by
Brandstätter et al. (2011). A possible lanarkite specimen has been
found by the authors at this site: a greenish-white prismatic crystal
spray within a quartz vug associated with anglesite.
Leadhillite Pb4(SO4)(CO3)2(OH)2
Leadhillite has been reported as gray tabular crystals up to 1 cm
associated with anglesite, cerussite and galena at the Van der Plas
mine.
Malachite Cu2
2+(CO3)(OH)2
Malachite is the most common copper mineral in the mining
area, occurring at all locations and in a variety of associations and
habits. The most common habit is fine, fibrous bundles and sheaf-
shaped spherical aggregates. These can reach up 3 cm in diameter,
and are found associated with all of the copper silicates, particularly
shattuckite. At the Kandesi, Okapanda and Okandawasi workings
these malachite spheres can also have a thin coating of transparent
crystalline quartz. Malachite is rarely present as primary crystals,
though some have been reported from the Kandesi prospect associ-
ated with quartz, calcite and dioptase (Schnaitmann and Jahn, 2010).
Malachite has been found in radial clusters and groups up to 3.2
cm in diameter, associated with shattuckite, wulfenite and quartz at
several localities including the Okatumba and Okarvizo prospects,
sometimes associated with small (less than 2 mm), yellowish white,
tabular wulfenite crystals.
Good pseudomorphs of malachite after azurite and cuprite have
been collected by the authors from the Okandawasi prospect. Mala-
chite pseudomorphs after native copper have been reported from
the Otjihowe prospect, as dendrites up to 1.8 cm (Schnaitmann and
Jahn, 2010). These pseudomorphs are said to be typically found
embedded in chrysocolla and are similar appearance in appearance
to specimens from the White Pine mine in the Keweenaw Peninsula
(Wilson and Dyll, 1992).
Mimetite Pb5(AsO4)3Cl
Mimetite, like other arsenates, is rare in the Kaokoveld district. It
occurs as millimeter-sized, yellowish white barrels with conichalcite
and galena at “anomaly G” near the Kandesi prospect.
Mottramite PbCuVO4(OH) to (Pb,Ca,Bi)VO4(OH,O)
Mottramite is present throughout the Kaokoveld area as dark green
to olive-green crusts, and also as lime-green crusts showing a high
bismuth content, particularly at the Christoff and Okandawasi pits
where it coats dioptase and is associated with beyerite.
At the Onderra workings, dark green mottramite coats wulfenite
and has produced pseudomorphs of wulfenite on calcite. Mottramite
also occurs as a coating as thin coating on dioptase and as inclusions
in quartz at the Okatumba mine.
Namibite Cu(BiO)2VO4(OH)
Namibite has been reported by Niedermayr et al. (1978) from
the Kandesi prospect, where it forms small patches of dark green
platy crystals associated with other bismuth minerals and chryso-
colla. It has also been identified as bright green, complex crystals
associated with beyerite, bismuth-rich mottramite and chrysocolla
from the Christoff mine.
Planchéite Cu8(Si4O11)2(OH)4?H2O
Planchéite is widespread throughout the mining district, generally
as a replacement of first-generation dioptase but is generally coated,
at least in part, by shattuckite and chrysocolla. The best specimens
have been recovered from the Okandawasi and Kandesi pits.
Platternite PbO2
Plattnerite is a rare mineral found as brown crusts associated
with cerussite at the Van der Plas mine.
Pyromorphite Pb5(PO4)3Cl
Although not identified in this study, pyromorphite has been
reported as small yellow crystals associated with shattuckite at the
Okatumba workings (Schnaitmann and Jahn, 2010).
Quartz SiO2
Quartz is the main gangue phase in the breccia mineralization
throughout the area. It occurs as massive white quartz (as at the
Omaue mine) and as smoky and yellow-orange hematite-included
terminated crystals. The best crystals have come from the Kandesi
and Christoff mines. At least two generations of quartz can be dis-
cerned in the mineralization: a massive, milky white quartz that also
hosts sulfide mineralization, and a second generation of generally
smaller but better developed crystals, some reaching up to 10 cm
in length (Schnaitmann and Jahn, 2010). Inclusions of chrysocolla,
shattuckite, planchéite and (more rarely) dioptase have been seen
in second-generation quartz.
Figure 23. Malachite pseudomorphs after
cuprite, 3.3 cm, from Kaokoveld. Luis
Burillo specimen; Jeff Scovil photo.
The Mineralogical Record, volume 44, July–August, 2013
14
Although not as well-developed, these crystals are reminiscent of
the Messina mine quartz crystals that contain inclusions of ajoite
and planchéite.
Scrutinyite -PbO2
Scrutinyite has been reported by Brandstätter et al. (2011) from
Van der Plas mine; the mineral is indistinguishable physically from
plattnerite.
Shattuckite Cu5(Si2O6)2(OH)2
The Kaokoveld district has without produced doubt the finest
shattuckite specimens in the world (Bowell and Cook, 2009).
Typically it occurs as concentric radial aggregates growing on
planchéite, often with a velvet-like appearance. It is generally the
next to last copper silicate mineral to form, succeeded only by
second-generation dioptase. Shattuckite can also occur as botryoidal
Figure 26. Quartz
crystals on shattuckite,
4 cm, from Kaokoveld.
Neil and C. Prenn;
Jeff Scovil photo.
Figure 24. Shattuckite pseudomorph after a
quartz crystal, 9 cm, from Kaokoveld. Marshall
Sussman specimen; Jeff Scovil photo.
Figure 25. Quartz crystals on shattuckite,
6 cm, from Kaokoveld. Neil and C. Prenn;
Jeff Scovil photo.
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The Mineralogical Record, volume 44, July–August, 2013
aggregates coated by quartz. The most common form however is as
massive breccia cement and vein infilling associated with quartz,
calcite, malachite and chrysocolla.
The color varies somewhat from one locality to another, from
pale turquoise-blue as at the Kandesi and Omaue workings, to a rich
dark blue color as at the Okandawasi pit. The color in the spherical
aggregates ranges from a darker blue in the center to a pale blue
rim or the reverse. As with dioptase, it is often found partially or
completely coated by quartz, and excellent examples of this have
been recovered from the Christoff mine and the Okandawasi pits.
Shattuckite is associated with most of the other minerals but par-
ticularly with planchéite, chrysocolla and quartz.
Shattuckite pseudomorphs after quartz and first-generation
dioptase have been collected from the Okandawasi pits. Shattuckite
pseudomorphs after 3-cm quartz crystals have been reported from the
Okatumba workings (Niedermayr et al., 2008). A single specimen
of shattuckite after wulfenite has been reported from the Okatumba
workings (Schnaitmann and Jahn, 2010).
Silver Ag
One specimen of a silver wire on goethite, chrysocolla and calcite
is known from Okandawasi pit. The two wires are approximately
2 to 4 mm in size.
Tenorite Cu2+O
Tenorite has been described from the Omaue mine where it
occurs as thin, dull black crusts associated with iron oxides. Given
its lack of distinguishing features in hand specimen and its simple
chemistry, many more unrecognized occurrences are likely to exist.
Vanadinite Pb5(VO4)3Cl
Only one occurrence of vanadinite has been previously reported
from the Kaokoveld district, from the locality at Otjintheka (Nie-
dermayr et al., 2008). No similar occurrence has been discovered
in the lead-rich mineralization near the Otuani workings or at Van
der Plas mine, and neither locality contains anomalously high vana-
dium concentrations (less than 100 mg/kg, similar to mineralization
throughout the district).
Wulfenite PbMoO4
Wulfenite, though not abundant except at the Onderra pit, is
widespread throughout the district and occurs in a range of colors
Figure 27. Drusy quartz on shattuckite on
quartz, 7.5 cm, from Kaokoveld. Martin
Zinn collection; Jeff Scovil photo.
Figure 28. Malachite (non-
pseudomorphous) in a shattuckite-lined
pocket, 8.2 cm, from Kaokoveld. Marcus
Budil specimen; Jeff Scovil photo.
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Figure 31. Malachite (non-
pseudomorphous) in a shattuckite-lined
pocket, 5.7 cm, from Kaokoveld. Jeff
Starr collection; Jeff Scovil photo.
Figure 29. Shattuckite on a quartz crystal,
6 cm, from Kaokoveld. ICS specimen; Jeff
Scovil photo.
Figure 30. Malachite (non-
pseudomorphous) in a shattuckite-lined
pocket, 9.2 cm, from Kaokoveld. Martin
Zinn collection; Jeff Scovil photo.
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The Mineralogical Record, volume 44, July–August, 2013
from pale white through lemon-yellow, orange, yellowish brown and
dark brown. Crystal size also varies considerably, from millimeter-
size up to a reported 15 cm (Schnaitmann and Jahn, 2010).
At the Onderra pit and at the Van der Plas mine, where the largest
wulfenite specimens have been reported, they are commonly found
coated with kaolinite, goethite, malachite and mottramite. Generally
the habit is tabular, although some prismatic crystals have also been
collected. A common assemblage is wulfenite with shattuckite and/
or dioptase. At the Okandawasi pit small plates of lemon-yellow
to orange-yellow wulfenite occur associated with shattuckite in
quartz. Typically these form small millimeter-sized crystals. The
most visually stunning combinations are the wulfenite-dioptase
specimens from the Omaue mine, also reported from the Kandesi
pit (Schnaitmann and Jahn, 2010). At the Otjindeka and Okatumba
workings wulfenite is commonly hosted by iron-stained and partially
corroded quartz; these wulfenite crystals display a darker central
core and many have corroded edges. The Okatumba and Onderra
Figure 32. Malachite (non-
pseudomorphous) on quartz-
coated shattuckite-lined pocket,
8.2 cm, from Kaokoveld. Rob
Lavinsky (The Arkenstone)
specimen; Joe Budd photo.
Figure 33. Malachite
(non-pseudomorphous) on
quartz-coated shattuckite-
lined pocket, 11.5 cm, from
Kaokoveld. Scott Rudolph
collection; Joe Budd photo.
The Mineralogical Record, volume 44, July–August, 2013
18
pits generally have produced the best quality wulfenite in the area
(Niedermayr and Schnaitmann, 2010).
ACKNOWLEDGMENTS
Much of the work that went into this paper arose out of supervis-
ing a mineral exploration program from 2008 to 2011 on behalf
of Sintez in the Kunene region, and the company is acknowledged
for allowing publication of the results. Ernst Van Dyke, Liubov
Egorova and Dmitry Guervich are acknowledged for their participa-
tion in the exploration work; they provided much of the geological
information presented here.
Figure 36. Wulfenite crystal group
with drusy quartz coating, X cm,
from Kaokoveld. Marshall Sussman
specimens Wendell Wilson photo.
Figure 34. Wulfenite crystals, X cm and X cm,
from Kaokoveld. Marshall Sussman specimens;
Wendell Wilson photo.
Figure 35. Wulfenite crystal, X cm, from
Kaokoveld. Marshall Sussman specimen;
Wendell Wilson photo.
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The Mineralogical Record, volume 44, July–August, 2013
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