A collector's guide to Onderra Mine, null: its geology, mining history and notable minerals, illustrated with the 29 specimens documented from this locality on EarthWonders.
Key facts
Onderra is one of the small but consequential specimen pits of the Kaokoveld copper district in northwestern Namibia’s Kunene Region, and for collectors its name is tied above all to wulfenite. The mine lies in the Opuwo Rural area on the Kaokoveld Plateau, in the same broad mineral province that made Omaue, Okandawasi, Kandesei, Christoff, Okatumba, Van der Plas and other workings familiar to collectors of Namibian secondary copper minerals. Geologically, Onderra is not a deep, industrial ore mine in the Tsumeb tradition; it is a small pit and associated subsidiary workings developed in lead-copper mineralization in limestone country rock, within a folded carbonate sequence of the Otavi Group where oxidized copper, lead, barium, molybdenum and vanadium species occupy quartz-carbonate veins, breccias, pockets and weathered ore shoots.
What makes Onderra important is the quality and distinct personality of its secondary assemblage. The best wulfenites are not the thin orange blades of Red Cloud or the chocolate plates of Ojuela, but chunky, yellow to honey-brown, sometimes pillow-like or bipyramidal crystals, often thick enough to feel almost sculptural. They may be freestanding, grouped, partly coated, or nested with dioptase, cerussite, malachite, calcite, quartz, baryte and dark green mottramite. Onderra also produced dioptase—less famous here than at Omaue or some other Kaokoveld pits, but locally significant where sharp, vivid green crystals occur with wulfenite, calcite, quartz or shattuckite. For the collector, the locality’s greatest specimens have the color-contrast punch that Kaokoveld is known for: warm wulfenite against white quartz or calcite, green dioptase flashing beside yellow-orange lead molybdate, and blue copper silicates turning what might have been a monochrome specimen into a miniature oxidized-ore landscape.
Regional View
Country View
The broader Kaokoveld district rose to collector attention because artisanal and small-scale specimen mining exposed rich oxidized copper-lead zones at shallow depth. Unlike large mechanized ore extraction, hand mining in narrow pits and pockets can preserve fragile secondaries—an important reason so many Kaokoveld specimens reached the market as attractive cabinet pieces rather than as ore. Onderra’s particular role in that story is as a wulfenite producer: not necessarily the most prolific source of every Kaokoveld species, but one of the names serious collectors watch for when they want Namibian wulfenite with real locality character.
Photo: Wikimedia Commons
Search for specimens: View all specimens from Onderra Mine, null
Onderra Mine is recorded as a mine in the Opuwo Rural constituency of Kunene Region, Namibia, on the Kaokoveld Plateau. Published locality data place it only approximately, around 18° S, 13° E, with a large margin of error; collectors should treat map points for the mine as regional guidance rather than field-navigation data. In specimen literature, Onderra sits in the cluster of Kaokoveld copper and lead occurrences roughly between Opuwo and Sesfontein, an area reached from the main road system but dependent on rough local tracks, dry riverbeds and seasonal access conditions.
The deposit is best understood as an oxidized, sediment-hosted lead-copper occurrence in carbonate rock. The Kaokoveld district is developed in rocks of the Damara orogenic system, with mineralization hosted mainly by Otavi Group carbonate sequences, including the Ombombo and Abenab units. In the broader district, the lower Ombombo succession includes interbedded limestones, slates, shales and dolomites and hosts many of the known copper occurrences; veins, stringers, stockworks and breccias carry quartz, calcite, baryte and base-metal sulfides such as chalcocite, galena, bornite and pyrite, later overprinted by oxidation. This supergene environment produced the collector minerals: copper silicates and carbonates, lead carbonates and molybdates, baryte, quartz and vanadate coatings.
Onderra itself was initially developed in 2005 on lead-copper mineralization in limestone country rock. It is described as a small pit, later extended by local Herero workers, with small subsidiary pits in the area yielding fine wulfenite. This is crucial: Onderra’s importance is not based on large ore tonnage but on the selective recovery of display-quality specimens from small oxidized pockets and weathered zones. Within the broader Kaokoveld mining area, the main mineral excavation styles range from large pits and box cuts to small trenches, and Onderra falls toward the small-pit end of that spectrum.
The mineralization is the classic Kaokoveld supergene mixture, but with a lead-molybdenum emphasis strong enough to make wulfenite the signature species. Wulfenite occurs with white quartz, calcite, malachite, dioptase, shattuckite, cerussite and mottramite, and pieces may show coatings or partial replacement by dark green mottramite. Some specimens are clean yellow to orange-yellow wulfenite crystals on pale matrix; others carry the more complex “mine-run” look of kaolinite-like clay, goethite, malachite or mottramite on or between crystals. Good wulfenite pockets here are judged by crystal completeness, edge preservation, color saturation, thickness, and whether the associated minerals add contrast rather than merely obscure the crystals.
Dioptase at Onderra is more complicated. Earlier district literature records small crystals to about 5 mm with wulfenite in white quartz and notes that some first-generation dioptase occurs with kaolinite-like matrix, spherical shattuckite aggregates and minor calcite, with much of that dioptase poorly preserved. Later market specimens show that the locality also produced more impressive dioptase groups: sharp, lustrous green crystals in vugs and on matrix, including cabinet-scale clusters and specimens with wulfenite. This later material has given Onderra dioptase a stronger collector presence than one might expect from the early literature alone.
Access for collecting today should be treated as controlled and permission-based. The locality is a mined prospect in a remote mineral district, not a public collecting site. Land access, mineral rights, operating status and local arrangements can change, and no collector should attempt to visit without explicit permission from the landowner and mineral-rights holder, current local guidance, and appropriate field safety planning. The mine’s best specimens entered the market through local miners, dealers and collection dispersals rather than through casual recreational collecting.
Wulfenite is the mineral that defines Onderra for collectors: yellow, honey, orange-yellow, yellow-brown to brown crystals, typically tabular to thick tabular but locally developed in striking bipyramidal or pillow-shaped forms that immediately separate Onderra from many better-known world localities. District literature reports Kaokoveld wulfenite from millimeter size up to exceptional large crystals, with the largest specimens associated especially with Onderra and Van der Plas; documented Onderra specimens include heavy bipyramidal crystals to about 6 cm across, and auctioned miniatures show deep yellow crystals to about 1 cm intergrown with cerussite, gemmy dioptase and malachite. The strongest Onderra pieces combine large, intact, lustrous or satiny crystals with pale quartz or calcite matrix and contrasting green dioptase, malachite, shattuckite or dark mottramite; ordinary pieces tend to be contacted, edge-worn, clay-coated, dull, or present as isolated crystals with little mineral context.
Dioptase from Onderra is valued less for abundance than for association and contrast: early descriptions note small crystals to about 5 mm with wulfenite in white quartz, plus first-generation dioptase in kaolinite-like matrix with spherical shattuckite aggregates and minor calcite, while later specimen-market records document sharp, lustrous, gemmy green crystals in vugs, individual crystals reaching roughly 1.1 inches on one sold piece, and matrix clusters several centimeters across. The best Onderra dioptase is vivid blue-green to emerald green, sharply crystallized, and set off by white quartz or calcite, blue shattuckite or chrysocolla, or small yellow-orange wulfenite crystals; lesser material suffers from the problem specifically noted for the locality—poor preservation, bruised crystal faces, coatings, or a color/matrix style close enough to Tsumeb that misattribution becomes possible unless the associated wulfenite-shattuckite-quartz assemblage is recognized.
Other documented minerals from Onderra include baryte, calcite, cerussite, malachite, mottramite, native copper and quartz, with mimetite listed historically but treated in modern locality data as an erroneous entry confused with baryte. Baryte is especially worth noting because transparent lemon-yellow blades to about 1.5 cm on white calcite have been reported from Onderra. Calcite ranges from transparent to milky white crystals, locally with dioptase in a combination reminiscent of classic Namibian calcite-dioptase specimens. Mottramite is more than a background coating: at Onderra it coats wulfenite and has produced pseudomorphs after wulfenite on calcite, giving the locality a distinctive vanadate-over-molybdate alteration theme. No accepted type-locality mineral is documented for Onderra in the major locality sources; its importance rests instead on specimen quality, association, and the way its wulfenite anchors the Kaokoveld suite.
The main authenticity issue with Onderra is not a wave of manufactured fakes, but locality confusion. Mindat notes that wulfenite from Onderra has often been erroneously sold as coming from “Okanadawasi/Kandesei,” and the broader Kaokoveld district is notorious for overlapping names, repeated farm names, prospect aliases, dealer-protected pocket names and historical labels. “Kandesei,” “Okandawasi,” “Old German mine,” “Kaokoveld mine,” “Otjikotu,” and “Onderra East/West” have all contributed to a fog of locality attribution in the region. For a serious specimen, an old label alone is helpful but not decisive; association, habit and provenance should all be weighed.
A second mislabeling trap runs in the opposite direction: some Onderra dioptase can look deceptively Tsumeb-like, especially when the crystals are thick, sharp and deep green. At least one auctioned ex-Bob Reynolds specimen was corrected from a presumed Tsumeb attribution to Onderra after the association style was questioned. The clue was the combination: sharp dioptase with small orange tabular wulfenite and calcite sparkle, an assemblage far more consistent with the Kaokoveld material than with a routine Tsumeb label.
Condition matters greatly. Onderra wulfenite is often thick, but wulfenite remains brittle, and edge chips, contacted backs, incomplete terminations and bruised ridges are common. Some pieces carry coatings of clay, goethite, malachite or mottramite; these may be natural and locality-significant, but they can also obscure luster. Aggressive cleaning is risky. Fine wulfenite faces can be dulled by mechanical scraping, and dioptase is brittle enough that ultrasonic cleaning, acids and careless soaking should be avoided. Mottramite coatings and pseudomorphs should be preserved, not “improved” away, unless the work is being done by an experienced preparator with full disclosure.
No locality-specific fake or treatment problem is well documented for Onderra in the sources used for this guide. Repairs and stabilization are still realistic concerns because many specimens have delicate crystal contacts, friable oxidized matrix, and multiple generations of pocket minerals. Ask whether a specimen has been repaired, restored, stabilized, trimmed or chemically cleaned, especially for large wulfenite crystals, dioptase vugs, and mixed wulfenite-dioptase pieces.
Onderra availability is uneven. Small wulfenites and mixed Kaokoveld pieces appear periodically, but top examples—large yellow to honey crystals, rare bipyramidal habits, undamaged matrix specimens, and clean wulfenite-dioptase combinations—are not common. Cabinet-quality Onderra pieces tend to surface through established dealers, old collections, auction archives and occasional new Namibian shipments rather than as a steady mine supply. Handle all lead-bearing minerals, including wulfenite and cerussite, with normal mineral-collection hygiene: keep dust down, do not grind or cut without proper precautions, wash hands after handling, and keep specimens away from children who might mouth them.
The first good story at Onderra is really a story about names. In the Kaokoveld, a label can be almost as complicated as the mineralization. Early exploration reports reused names, local miners applied different names to nearby pits, and some sellers deliberately blurred localities to protect productive diggings. Onderra is both a real wulfenite locality and a name connected with exploration licenses farther south. Nearby pits acquired overlapping identities: Okandawasi, Kandesi, the Old German mine, and the Kaokoveld mine all circulated in the specimen trade. For collectors, the result is a generation of beautiful Kaokoveld labels that need careful reading. A specimen marked simply “Kandesei” or “Kaokoveld” may be honest, old and attractive—and still not precise.
Onderra itself entered the literature as a small pit opened in 2005. It was not described as a grand underground mine with regimented stopes and ore levels, but as a local working in limestone-hosted lead-copper mineralization, gradually enlarged by Herero workers. That small scale explains much of the locality’s appeal. These were not anonymous tons of ore; they were pockets and subsidiary pits worked closely enough that fragile secondaries had a chance to survive. When the pit was right, it yielded wulfenite that looked startlingly unlike what many collectors expected from Namibia: fat yellow crystals, sometimes more architectural than bladed, and good enough to make dealers and collectors reassess what Kaokoveld could produce.
One of the most memorable Onderra specimens reached public attention through the Charlie Key and Marshall Sussman collections: a small-cabinet wulfenite measuring 7.7 x 5.6 x 4.8 cm, with huge thick bipyramidal crystals to about 6 cm across. The specimen was described as having been found around 2007–2008 during exploratory mining at the prospect, and its habit was considered extraordinary for wulfenite, whose bipyramidal crystals are more often seen at far smaller sizes. It was not merely a large Namibian wulfenite; it was a large wulfenite in a habit that made seasoned collectors stop and look twice.
At the 2013 Westward Look Fine Mineral Show in Tucson, Onderra was visible in another way: as loose, large wulfenite crystals. A show report from the floor noted that Red Gallery and E-shop Mineralien had a selection of large Onderra wulfenite crystals, mostly single crystals without matrix, with some several centimeters wide. That matters because it captures how the locality entered the market. Onderra was not always represented by textbook matrix specimens; it also produced hefty single crystals compelling enough to sell on their own.
Then there is the Bob Reynolds correction, a cautionary tale every label-conscious collector should remember. A thumbnail specimen in an online auction had belonged to Bob Reynolds, former Curator of Earth Sciences at the San Bernardino County Museum and the namesake of reynoldsite. The piece was initially assumed to be Tsumeb because the dioptase was so good: deep emerald green, thick, sharp and lustrous. Then someone looked harder at the association. The crystals were accompanied by stark orange tabular wulfenite to 6 mm and a little drusy white calcite, a combination whose style pointed away from Tsumeb and toward Onderra. The corrected label turned the specimen into something arguably more interesting: not just another good dioptase, but a compact lesson in how paragenesis can catch a famous label in the act of being wrong.
A later market note adds a small, vivid pocket story to the Onderra record: a 3.8 x 3.4 x 2.8 cm miniature of blue shattuckite balls sitting directly on bright green dioptase. The dealer emphasized that shattuckite balls were usually seen on malachite, not on lustrous dioptase, and described the piece as the only one of that quality and condition they had seen from the find. It is a reminder that Onderra is not exhausted as a collector idea. Even a locality known principally for wulfenite can occasionally deliver a pocket that changes what collectors expect to see on a label.
Bowell, Robert J.; Ermolina, Olga; van der Plas, Wim; van Us, Jesper; Steiner, Marius (2013), “Famous mineral localities: Minerals of the Kaokoveld District, Kunene Region, Namibia,” The Mineralogical Record, 44(5), 485–504. The key English-language overview for the district, with specific discussion of Onderra’s 2005 development, wulfenite, dioptase, mottramite, baryte and regional geology.
Schnaitmann, Ernst A.; Jahn, Steffen (2010), “Mineralien aus Schürfen im Kaokoveld, Namibia,” Mineralien-Welt, 21(2), 78–90. German article cited by Mindat for Onderra mineral occurrences including baryte, calcite, dioptase, mottramite, native copper, quartz and wulfenite.
Niedermayr, Gerhard; Schnaitmann, Ernst A. (2010), “Neuigkeiten aus Namibia,” Mineralien-Welt, 21(6), 89–96. Referenced on the Onderra locality page and important for the continuing documentation of new Namibian finds and Kaokoveld locality corrections.
Parker, Ronald L. (2021), “Dioptase – The Emerald Impersonator,” Outcrop, Rocky Mountain Association of Geologists, Vol. 70, No. 7. Includes illustrated discussion of Onderra dioptase specimens and places Kaokoveld material in the broader collector context of Namibian dioptase.
Allen, Nicole K.; Hitzman, Murray W.; Sarg, J. Frederick; Ellmies, Rainer (2016), “Structurally controlled Cu-Zn-Pb-(Co) mineralization in the Ombombo Subgroup, Kaokoland, Namibia,” Geological Society of America Abstracts with Programs. Regional geological context for Ombombo Subgroup sediment-hosted base-metal mineralization in Kaokoland.
Mindat: Onderra Mine, Opuwo Rural, Kunene Region, Namibia — The core locality page, with mineral list, alternate-name warning, references and photo links.
Wikimedia Commons: Category Onderra Mine — A useful public image archive of Onderra wulfenite specimens, many sourced from Rob Lavinsky/iRocks.
The Mineralogical Record article PDF: Minerals of the Kaokoveld District, Kunene Region, Namibia — The most useful single source for the district’s geology, mining history and specimen mineralogy.
Collectors Edge: Dioptase, Onderra Mine — Market example documenting a 7.5 cm wide recent-find dioptase cluster from Onderra.
Collectors Edge: Dioptase and Wulfenite, Onderra Mine — A documented wulfenite-dioptase combination with condition disclosure and dimensions.
Mineral Auctions: Dioptase with Wulfenite, ex Bob Reynolds, corrected to Onderra — A useful case study in Tsumeb/Onderra misattribution and association-based correction.
Mineral Auctions: Wulfenite and Dioptase on Cerussite with Malachite, Onderra — Good descriptive record of the yellow, pillow-like Onderra wulfenite style and mixed assemblage.
Well Arranged Molecules: Shattuckite balls on Dioptase, Onderra Mine — Notable dealer record for an unusual shattuckite-on-dioptase association from a recent Onderra find.
Kristalle 2013 Tucson Show Report — Contemporary show-market note on large single wulfenite crystals from Onderra.
