New Cornwall Mine, Kadina, South Australia — a classic copper-oxide locality famed for emerald-green, lustrous atacamite crystals and its collector prestige.
Key facts
New Cornwall Mine is the great classic locality for Australian atacamite: a small nineteenth-century copper mine east of Kadina on northern Yorke Peninsula, South Australia, whose best specimens have become benchmark pieces for the species. The mine belongs to the historic Moonta-Wallaroo copper province, the celebrated “Copper Triangle,” but it is mineralogically distinct from the better-known Wallaroo and Moonta workings. Its copper lodes cut low-grade Proterozoic metasedimentary rocks rather than the more intensely metamorphosed Wallaroo schists or the Moonta porphyry lodes, and its oxidized zone developed under dry, saline groundwater conditions ideal for the formation of copper chlorides.
The collector importance of New Cornwall rests on the dark green, chisel-terminated atacamite crystals recovered during the early productive years of the mine. Specimens attributed to this locality include lustrous prismatic “sticks,” isolated single crystals, crystal groups in vugs, and pieces in yellow-brown limonitic gossan or grey siltstone. The finest nineteenth-century examples are not merely good atacamite; they are among the defining mineral specimens of South Australia, and many entered institutional collections under old labels, some of which misassigned them to Burra before later research restored them to Kadina.
The assemblage is a copper-oxide-zone suite dominated by atacamite, with paratacamite, malachite, azurite, native copper, chalcocite, chalcopyrite, pyrite, goethite, quartz, gypsum, anatase and related secondary minerals recorded from the locality. For most collectors, however, “New Cornwall” means the best of one thing: transparent to translucent, lustrous, dark emerald to nearly black-green atacamite crystals, often in protective cavities where their terminations survived with unusual sharpness.
Regional View
Country View
New Cornwall is also a locality where labels matter. The mine was worked briefly and intensively, then effectively disappeared as a productive source; later dump collecting yielded mainly small crystals and micromount material. Large, sharp, matrix-supported crystals with old provenance are therefore a different collecting category from modern or late-collected dump specimens. The best pieces show depth of colour, glassy to adamantine luster, intact chisel terminations, and a believable New Cornwall matrix rather than an anonymous green copper-chloride crust.
Photo: Rob Lavinsky, iRocks.com, via Wikimedia Commons
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New Cornwall Mine, also known historically as the Cornwall Mine, Kadina Mining Co. ground, Wallaroo East, and in later collecting lore as the Pig Pen or Piggery Mine, lies near Kadina on the Copper Coast of South Australia, roughly east of the main Wallaroo mines. Its position in the Moonta-Wallaroo district is important: this was one of Australia’s great nineteenth-century copper fields, but New Cornwall was a separate venture rather than simply a shaft of the Wallaroo operation.
Geologically, the mine worked copper lodes in the Wandearah Metasiltstone area east of Kadina. Regional geological work describes the New Cornwall and nearby Wandilta lodes as trending northwest and dipping steeply southwest, with generally siliceous character. In hand specimen terms, that fits the classic pieces: atacamite in cavities in iron-rich gossan, yellow-brown limonitic matrix, grey siltstone, and vuggy material with small clear quartz crystals. The oxidized zone of the broader Moonta-Wallaroo field extended roughly 30 to 50 metres, and saline groundwater helped make atacamite the dominant secondary copper mineral in those upper workings.
Copper was discovered at the New Cornwall ground in 1861, during the speculative rush that followed the Wallaroo and Moonta discoveries. The New Cornwall Mineral Association was formed with a nominal capital of £50,000, a substantial sum for a young colonial venture, and the mine was soon equipped with steam power and surface plant. Early descriptions place about forty-five men at work while the operation was being established, with ore-reducing works planned around a patented process by R. V. Rodda. The processing venture was troubled: a smelter was constructed in 1862, but disputes and uncertainty over the process limited its life.
Water was a major operating problem, as it was at so many Cornish-style copper mines. In 1863 a Cornish beam engine was imported from Cornwall to drain the mine below the 50-metre level. By 1866 the mine reportedly employed about 100 men, but the enterprise never became the dividend-paying success its backers hoped for. By the time it closed in 1870 it had produced an estimated 5,000 tons of ore after very heavy expenditure, and recorded copper production between 1864 and 1867 was valued at £20,386.
The surface plant had a long afterlife in the district. In the 1880s the engine buildings and machinery were sold to the Wallaroo Mining & Smelting Company, and the large pumping engine was dismantled and re-erected at Elder’s Shaft at Wallaroo Mines. Stone from the New Cornwall engine house was later reused in Kadina, including in the Roman Catholic church building, a characteristic fate for early mine masonry in the Copper Triangle.
Specimen production appears to have been concentrated in the early years, probably between about 1862 and 1867, when the richest oxidized-zone material was opened. The famous large crystals were likely taken from a single major pocket or a small series of pockets rather than from a long-running succession of finds. Old records mention “muriate of copper,” the historic name applied to atacamite, along with native copper and malachite-bearing ore. One early account also noted a huge block of ore, said to weigh nearly five tons, sent to the 1862 International Exhibition in London; later writers have wondered whether this was connected with a public-exhibition specimen of chalcocite and malachite recorded from the mine.
Later collecting was far more modest. Dump collecting in the twentieth century produced attractive small atacamite crystals, commonly 1 to 3 mm and occasionally up to about 10 mm, often with malachite. Those pieces are significant for micromount collectors and for confirming the distinctive New Cornwall matrix, but they should not be confused with the great nineteenth-century crystals that made the locality famous. During the 1970s and 1980s, while the property owner operated a small piggery, collectors could obtain permission and recover material from the dumps. In the mid-1990s, however, the property changed hands and much of the remaining mine landscape was filled or rehabilitated. Since 1998 the land has been private property associated with a church; collecting or visiting requires explicit permission from the landholder, and the old workings should not be regarded as an open fossicking site.
Atacamite from New Cornwall Mine is the locality’s signature mineral and one of the standards by which the species is judged: dark green to nearly black-green, lustrous orthorhombic prisms, typically elongated and chisel-terminated, occurring as single crystals, bundles, and crystal groups in vugs in limonitic gossan, grey siltstone, or quartz-lined cavities. The old classic crystals are vastly larger than the later dump material; historic accounts and later summaries report crystals exceeding 10 cm, with exceptional single crystals much larger, while twentieth-century dump finds were usually micromount-sized, commonly 1 to 3 mm and only rarely approaching 10 mm. Good New Cornwall pieces show sharp form, glassy luster, intact terminations, and convincing old matrix; ordinary examples are small crusts, broken crystals, or dark green patches without crisp morphology.
Other documented minerals from New Cornwall include paratacamite, malachite, azurite, native copper, chalcocite, chalcopyrite, pyrite, goethite, quartz, gypsum and anatase. New Cornwall is not known as a type locality; its distinction is instead specimen quality, especially for atacamite and its copper-chloride associates. Paratacamite is the most important rarity in the assemblage because it belongs to the same basic copper chloride family and can occur in similar green material, making analytical confirmation valuable. Malachite is also notable because New Cornwall was one of the relatively few mines in the district where it occurred in appreciable quantity; azurite appears much less common. Native copper, chalcocite and chalcopyrite anchor the supergene assemblage back to the original copper ore system, while quartz and goethite are important matrix clues for locality attribution.
New Cornwall atacamite is a locality where provenance is part of the specimen. Fine nineteenth-century crystals may have passed through several collections, and older labels can be wrong: a persistent historical misattribution placed some New Cornwall-type crystals at Burra, South Australia, about 100 km away. Modern locality correction is based on specimen style, matrix, historical research, and comparison with confirmed Kadina material. A label reading “Burra” on a large, dark, chisel-ended atacamite should therefore be treated with caution rather than accepted at face value.
The other common mislabelling problem runs in the opposite direction: specimens from Mount Gunson and other South Australian atacamite localities have sometimes been labelled New Cornwall because they also occur on limonitic or goethitic matrix. New Cornwall matrix is often distinctive: vuggy yellow-brown limonite or gossan, grey siltstone, and cavities with small clear quartz crystals. Mount Gunson material may look superficially similar, so important specimens deserve careful comparison, especially if they lack old labels or credible chain of ownership.
Condition is critical. Atacamite crystals are brittle, and the best New Cornwall habit is long, slender, and exposed; broken tips, bruised edges, repaired crystals, and glued-in loose prisms should be checked under magnification. Matrix pieces in protective pockets are strongly preferred because the cavity walls shield terminations. Loose single crystals can be legitimate, but they need especially good provenance because detached “green sticks” are hard to place confidently.
No major treatment tradition is documented for New Cornwall atacamite, but standard copper-mineral cautions apply. Avoid washing specimens aggressively, soaking them, exposing them to acids, or storing them in damp conditions. The limonitic and siltstone matrices can be soft or friable, and old collection pieces may carry dust or iron oxide that is better left alone than over-cleaned. Atacamite is not collected here for fluorescence, and fluorescence should not be expected as an identifying feature.
Market availability is split between two very different categories. Small dump-collected pieces and micromounts appear occasionally and can be affordable, especially when the crystals are only millimetric. Classic cabinet-quality pieces with sharp centimetre-scale crystals are genuinely scarce, and the best old examples have moved into museums or long-held private collections. A recent dealer listing for a 40 x 30 x 20 mm New Cornwall atacamite was priced in the four-figure range, while exceptional historic crystals with size, luster, and provenance can command much more. Conversely, low-grade or poorly crystallized atacamite from old collections may sell modestly; the name alone does not make a specimen important.
The New Cornwall story begins in the speculative heat of 1861, when northern Yorke Peninsula changed from dry pastoral country into one of the busiest copper districts in the Australian colonies. The New Cornwall Mineral Association was formed in April of that year with 25,000 shares at £2 each, and its leases covered fifteen eighty-acre sections. Even before the mine was fully proved, the company had about forty-five men at work, an engine with a twenty-one-inch cylinder, carpenter’s shops, a smith’s shop, offices, and plans for ore-reducing works. The scale of ambition was unmistakable: this was not a scratch-and-hope prospect but a financed attempt to build a Cornish-style copper mine in the Australian bush.
The Rodda smelting process gives the mine one of its more curious early episodes. Arrangements were made to install ore-reducing works at New Cornwall using a patented method devised by R. V. Rodda, and specimens illustrating the process were forwarded to the International Exhibition. It was a very nineteenth-century mixture of innovation, promotion, and risk: a new mine, a patented metallurgical promise, and mineral specimens sent abroad as proof that Kadina could stand with the mining districts of the wider empire. Yet the process did not become the mine’s salvation. The smelter was built in 1862, closed amid dispute in 1863, revived briefly in 1864, and then ceased again.
Then there is the great exhibition block, a detail too large to ignore. Early records mention a copper ore block from New Cornwall said to weigh nearly five tons and sent to the 1862 International Exhibition in London. Another later account records a beautiful public-exhibition specimen of grey ore and green carbonate: chalcocite and malachite. Whether these accounts describe the same showpiece or two related exhibition specimens, the image is vivid — a massive piece of Kadina copper ore, lifted from a young mine on Yorke Peninsula and shipped halfway around the world to demonstrate colonial mineral wealth. Its later fate is unknown.
The mine’s most collectible story is quieter but more consequential: the attack of salty groundwater on copper ore. In the oxidized zone, the chemistry favoured basic copper chlorides, and cavities opened in gossan and siltstone became lined with dark green atacamite. At some point in the 1860s, miners encountered the pocket or pockets that produced the famous crystals. They were likely recovered as ore, curiosities, or both, before mineral collecting had the careful specimen-saving culture it developed later. That so many sharp crystals survived at all is remarkable. Some went into museums around the world; others drifted through private collections with only imperfect locality memory.
The labels became a second history. For years, some of the greatest Australian atacamites were said to be from Burra, another famous South Australian copper district. The error was plausible enough to persist in literature and collections, but the specimens themselves told a different story: their habit, matrix, and historical context pointed back to New Cornwall and the Kadina field. For collectors, that correction is not academic. It changes the meaning of a specimen from “fine South Australian atacamite” to “one of the classic New Cornwall crystals,” a very different place in mineral history.
New Cornwall also has an unexpectedly domestic collecting chapter. In the 1970s and 1980s, the mine property was associated with a small piggery, and collectors remembered the owner as amenable to visits. The old workings were already long abandoned, but dump material still yielded small green crystals, often in limonitic cavities or with malachite. These were not the giant nineteenth-century “sticks,” yet they kept the locality alive for micromount collectors and gave later generations a chance to handle real New Cornwall material from the ground itself.
The final chapter is one of loss. In the mid-1990s, after the property changed hands, pits and shafts were filled with mine dump material and the area was replanted, destroying much of what remained of the old mining fabric and making underground exploration impossible. In 1998 the property was purchased by a church, placing the locality firmly on private land. Today the mine survives principally through specimens, labels, literature, and a few historical traces in Kadina — including stone from the old engine house reused in town.
Wilson, Wendell E. (2019). “Atacamite from the New Cornwall mine, Kadina, South Australia.” The Mineralogical Record, 50(2), 169–199. The key modern article dedicated specifically to the mine, its history, mislabelled specimens, and classic atacamite production.
Pring, A. (1988). “Minerals of the Moonta and Wallaroo Mining Districts, South Australia.” The Mineralogical Record, 19, 407–416. Important district-level treatment cited in later reviews of Moonta-Wallaroo mineralogy, including the atacamite-rich oxidized zones.
Palache, C., Berman, H. & Frondel, C. (1951). The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Volume II. Classic systematic reference cited for New Cornwall atacamite in later locality summaries.
Austin, John Baptist (1863). The Mines of South Australia: Including also an Account of the Smelting Works in that Colony. Early colonial mining account, valuable for contemporary references to New Cornwall ore, native copper, and “muriate of copper.”
Brown, Henry Yorke Lyell; compiled by Lionel C. E. Gee (1908). Record of the Mines of South Australia, 4th edition. Government Printer, Adelaide. Historic mining compilation that records exhibition material and early mine history.
Conor, C. H. H. (1996). Metasomatites, magmatites, metasediments and metavolcanics: the Palaeo-Mesoproterozoic geology of the Moonta-Wallaroo Cu-Au district. Geological Survey of South Australia, RB 96/00046. Government geological field-excursion report covering the Proterozoic framework of the Moonta-Wallaroo district, including New Cornwall.
Preiss, W. V., compiler (1993). The Geology of South Australia, Volume 1: The Precambrian. Geological Survey of South Australia Bulletin 54. Includes regional geological context for the Wandearah Metasiltstone and New Cornwall-Wandilta area.
Mindat — New Cornwall Mine (Cornwall Mine), Kadina, South Australia — The most useful single online locality page, with coordinates, synonyms, mineral list, history, access notes, and specimen discussion.
Mindat — Atacamite from New Cornwall Mine — Species-specific occurrence page documenting New Cornwall atacamite as world-class for the species.
Mindat “Best of Atacamite” page — Comparative context for why New Cornwall atacamite is regarded as among the finest ever found.
Wikimedia Commons — Atacamite from New Cornwall Mine — Freely licensed photograph of a classic pocket specimen with dark green crystals in gossan matrix.
Royal Society of New South Wales PDF — Broken Hill Symposium proceedings, including Moonta-Wallaroo discussion — Useful regional mineralogical summary noting the saline oxidized-zone conditions and New Cornwall’s finest atacamite crystals.
SARIG catalogue extract — Conor 1996 Moonta-Wallaroo geology report — Government source for regional geological framework and named units around Kadina.
Geological Survey of South Australia Bulletin 54 — Precambrian geology — Broader geological background on the Moonta Subdomain and Wandearah Metasiltstone.
Mineralogical Record Vol. 50 No. 2 product page — Issue containing Wendell E. Wilson’s dedicated New Cornwall atacamite article.
Austin, J. B. — The Mines of South Australia (1863) — Early mining account from the period when New Cornwall was active.
Brown, H. Y. L. / Gee, L. C. E. — reference — Historical mining compilation with details later used in New Cornwall locality research.
MIM Museum specimen records reproduced through Mindat photo imports. Notable museum-held New Cornwall atacamites include pieces with centimetre-scale dark green crystals, such as a 7.5 x 7.5 x 9 cm specimen with a 4 cm crystal and another 2.5 x 3 x 5 cm example with a 3.5 cm main crystal.
Minfind archived listing — Atacamite from New Cornwall Mine — Market reference for a 40 mm New Cornwall atacamite specimen offered by The Arkenstone.
Mellors & Kirk catalogue — Roger Harker Collection lot including New Cornwall atacamite — Recent auction context for more modest New Cornwall material.
