Copper

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Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities? After each set of pictures there should be some descriptive text. If none appears it means that we need someone to tell us about the specimens from that locality and something about the geology of the occurrence.


Copper
Cu Isometric



Copper specimens are readily available. "Nuggets" of native copper from the Keweenaw peninsula of Michigan USA are available from many tourist shops in the US. While most are modestly priced some large "classic" specimens can be sold for 5 figure $ amounts.

Copper has been very important as a metal from which tools are made since the 5th millennium BC in the Middle East and slightly later in Europe. It was the first metal to be used in tools and was obtained not only as the native metal, but was smelted from other minerals. When copper is mixed with tin or arsenic, the alloy bronze is produced which has superior properties as compared to the pure copper. The use of copper as an electrical wire led to a large increase in demand and production of the metal.

Native copper is widespread in the oxidized zone of copper deposits, but even in these deposits is a relatively minor ore mineral. Copper is also found associated with basalts, but the only place it was a major ore mineral was in the Keweenaw peninsula. Copper is also a major ore mineral as a cement in the sedimentary rocks at Corocoro.


Copper
Australia
New South Wales, Yancowinna Co., Broken Hill

Copper, 5.1cm tall	© Rob Lavinsky

Copper, 6cm tall	© Dan & Diana Weinrich Minerals

The best specimens were found in the oxidized ores in the Propietary and Block 10 mines. The common forms were arborescent groups, "cylindrical" crystals and flattened spear shaped crystals.


Copper
Bolivia
La Paz Department, Pacajes Province, Corocoro

Copper after Aragonite, 2.4cm tall	© Carles Millan

Copper after Aragonite, 1.5 cm	© Rob Lavinsky

Corocoro is well known for the native copper replacement of hexagonal aragonite twins, which occur embedded in poorly consolidated Miocene sandstones and mudstones. Like the Keweenaw district, production of native copper was significant. In some small areas of the Corocoro district, the pseudomorphs themselves constituted the main ore and were dug up by the thousands, although desirable specimens (ie. well shaped ones with a high degree of replacement) were only a tiny fraction of total ore production, most of them being misshapen and/or only slightly replaced. When I visited one of the pseudomorph mines in the 1990s, miners were digging with picks and shovels in short adits, carting the pseudomorphs in wheelbarrows several hundred metres down to a creek to wash the mud off. Specimens were mainly available for purchase from the miners' wives, who highgraded the better looking ones for sale to visiting dealers. (Alfredo Petrov, September 2010)

Copper
Canada
Ontario, Algoma District, Mamainse Point Copper Area

Copper, 14cm wide	© D.K.Joyce

Copper 9cm	© D.K.Joyce

Deposits form in Keweenaw lavas that correlate with the deposits in Michigan.

Copper
Chile
Coquimbo Region, Elqui Province, La Serena, Talcuna Cu-Mn-Ag Mining District, Coca-Cola Mine



Copper
China
Hubei Province, Huangshi Prefecture, Daye Co., Edong Mining District, Fengjiashan Mine (Daye Copper mine)

Copper, 4.8cm tall	© Jiangbin

Hungary, Rudabányai Mts., Rudabánya



Kazakhstan, Zhezqazghan Oblysy, Dzhezkazgan



Kazakhstan, Zhezqazghan Oblysy, Itauz Mine

An open pit mine that began operations in the late 1990's. Production at a rate of 2 Mt/yr from red sandstones of the Permian-Carboniferous age. Small amounts of specimens have been reaching the mineral market since about 2001. Main types of specimens include spinel twins, and groups 3 to 20 cm long.

11 cm	© fabreminerals.com

4 cm	© Joseph A. Freilich

4 cm	© Rob Lavinsky

Namibia, Windhoek District, Ogonja

Deposits in the district are of the Tsumeb type with copper and molybdenum minerals in a vein of quartz breccia. The mines are better known for their cuprite and malachite specimens. Copper occurs as masses and filigrees of delicate crystals. Crystals with the cube, dodecahedron and octahedrons occur up to 3cm in size. Specimens of copper containing up to 400kg were known and a 150kg specimen is in the Geological Survey museum in Pretoria. Most of the native copper was found in the first 50 meters of the mines.



Namibia, Windhoek District, Ogonja, Emke Mine

5 cm	© Rob Lavinsky

Namibia, Windhoek District, Ogonja, Ogonja Mine

3.5 cm	© Rob Lavinsky

UK, England, Cornwall



UK, England, Cornwall, Botallack Mine




UK, England, Cornwall, Tresavean Mine



UK, England, Cornwall, Relistian Mine



USA, Arizona
This state in the southern Basin and Range Province has numerous porphry copper deposits.

USA, Arizona, Cochise Co., Bisbee

6 mm	© Dave Richerson

Campbell shaft, 3 cm	© Rob Lavinsky

USA, Arizona, Greenlee Co., Morenci Mine



USA, Arizona, Pima Co., Ajo District

2 cm	© Rob Lavinsky

2 cm	© fabreminerals.com

USA, Arizona, Pima Co., New Cornelia Mine

3 cm	© fabreminerals.com

5 cm	© Rob Lavinsky

USA, Arizona, Pima Co., Mission Mine

Copper inclusions in gypsum.



USA, Arizona, Pinal Co., Ray Mine

3 cm	© Jasun McAvoy

6 cm	© RWMW

USA, Arizona, Pinal Co., Ray Mine, Pearl Handle pit




USA, Michigan, Keweenaw Peninsula

The Keweenaw deposits occur over a length of approximately 150 miles in a band of deposits that usually are less than 10 miles wide. They occur primarily in precambrian basalts and interflow conglomerates. Most of the copper is very pure, with some areas having minor amounts of arsenic and very rare sulfides. Gangue minerals include calcite, quartz, prehnite, epidote, chlorite and zeolites. Chunks of copper were transported as far south as Illinois by glaciers.

The first exploitation of copper was begun by Native Americans over 6800 years ago. It is estimated that they produced between 100 and 500 million pounds of copper. Almost all of the later mines had been found and exploited during this period. ommercial mining began in the 1840's with the mining of the fissure veins. Large scale industrial production of the flow deposits and conglomerates started in the 1880's and the last commercial mine closed in the 1990's. Total production has been 11 billion pounds of copper. With one exception the mine shafts followed the dip of the beds and reached lengths up to 9200 feet (Quincy).



The Seaman museum in Houghton has the best collection of native copper from the Keweenaw.
Virtual Keweenaw field trip

6 cm	© fabreminerals.com

hoppered 4 cm	© Rob Lavinsky

3 cm	© Rob Lavinsky

Copper silver "halfbreeds" are fairly common, but except for a few believed to be created by glacial action, most of these specimens come from the stamps used to reduce the ore.

To mine the large masses of copper that were found in the fissure mines, they had to be chiseled apart so they could be removed from the mines. There are numerous copper "chips" from these attempts that have been found on the poor rock piles in the district. Some miners made "fans" as demonstrations of their ability to do precision cuts as well as for sale to tourists. These examples are relatively rare from the Keweenaw.


USA, Michigan, Houghton Co., Calumet & Hecla Mine



USA, Michigan, Houghton Co., Quincy Mine

7 cm	© Joseph A. Freilich

USA, Michigan, Houghton Co., Kearsarge Mine



USA, Michigan, Houghton Co., Osceola Mine

Known for the large wire that have been found.




USA, Michigan, Houghton Co., Champion Mine

Mines in the Painesville area are most likely to consist of the ferny growth habit.

20 cm	©

5 cm	© Dan & Diana Weinrich Minerals

USA, Michigan, Keweenaw Co.



USA, Michigan, Keweenaw Co., Ahmeek mine

cm


USA, Michigan, Keweenaw Co., Central Mine

8 cm	© Rob Lavinsky

USA, Michigan, Keweenaw Co., Gull Rock

7 cm	© Rob Lavinsky

USA, Michigan, Keweenaw Co., Great Sand Bay

This specimen is illustrative of the large masses that were encountered in the fissure mines in the region. This was raised from the bottom of Lake Superior.

USA, Michigan, Keweenaw Co., Cliff mine


USA, Michigan, Keweenaw Co., North Cliff Mine



USA, Michigan, Keweenaw Co., Northwestern Mine



USA, Michigan, Keweenaw Co., Prospect Point

In 1990 a small vein (45 feet long) was found that contained some of the largest dodecahedral and steep tetrahexahedral copper crystals in the district. Approximately 1000 specimens were found. The largest weighed 14 pounds.



USA, Michigan, Ontonagon Co.




USA, Michigan, Ontonagon Co., White Pine Mine

The White Pine mine was relatively unique in that a large portion of the copper mined consisted of sulfides. This mine also produced large sheets of native copper from fractures in the shale.

15 cm	© Rob Lavinsky

6 cm	© Rob Lavinsky

8 cm	© Joseph A. Freilich

7 cm	©

USA, Nevada, Elko Co., Mountain City Mine

5 cm	© Rob Lavinsky

USA, New Mexico, Grant Co., Copper Rose Mine

This mine is known for the native copper pseudomorphs after rosettes of azurite crystals.

3.5 cm	© Rob Lavinsky

USA, New Mexico, Grant Co., Chino Mine

The Chino mine is a typical porphry copper deposit. Early mining was concentrated in high grade areas where the ores had been enriched by supergene processes. This was then followed by development of a large open pit to mine lower grade ores. Most copper specimens from the mine are open fracture fillings of native copper. These plates can reach several feet in length. Also there have been some fern like growths in these narrow fractures. In summer of 2001 a boulder was found that yielded about 50 specimens of stout spinel twins. In 2006 a pocket was hit in the pit that yielded about 200 specimens ranging from thumbnail to 8cm in size.

5 cm	© Rob Lavinsky

7 cm	© Rob Lavinsky

8 cm	© Rob Lavinsky

USA, Washington, Jefferson Co., Beaver Valley Quarry

2 mm	©

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Edited 33 time(s). Last edit at 11/03/2011 06:24PM by David Von Bargen.

Great work David!!!

Good work!

Rock Currier
Crystals not pistols.

Great work, David!! And thank you for using one of my photos in the article.

As far as Keweenaw geology and history; I may be able to give you more specific information on the geology of the copper deposits and the history of copper mining there. Shoot me a PM or an email and let me know what information you want/need.

Just tell David the things he doesn't knowX(

Over the years some people become quite knowledgeable about specimens from various localities, or if not very knowledgeable, they still hold knowledge that few other people have. This project was created with the hope that it would provide a place for them to put this knowledge rather than let it die with them. If you know some good stuff about a locality and the specimens from there, write it down and put it here. It is easy when working on this project to come to realize that you really don't know very much at all, but that should not stop you from sharing the few things you know with the rest of us. The pictures that we place in these articles are nice and we want to use the best ones we can get, but in the long run, it will be the writing below the images that will be the most important part of the project. Picking out the pictures and arranging them is of course the easiest part and the most fun part and it will be these that will attract attention to the project and hopefully bring knowledgeable people to us and encourage them to tell us what they know about the specimens and the localities.

Rock Currier
Crystals not pistols.

As a copper specialist, I love this page. Great work. I have a number of good specimens that are from locs not represented here, but will need to think hard about which might actually qualify for this type of "Best..." page before I'd bother to suggest any.

One erroneous bit I spotted, though: one of the pics for the White Pine mine above is actually linking to a quartz from Poland. Suspect this is a cut-and-paste gone awry?

Cheers,
D.

Actually the photo was replaced after a new shot was uploaded later.

We tend to be a little loose with the term "Best". Halfway decent crystals will probably get included (massive material won't unless it is real big).

or real pretty!!!

[www.mindat.org]

A minor correction - it's USA, Michigan, Keweenaw Co., Point Prospect

Rock,
Perhaps a call out for New Jersey coppers might generate some photographs. Franklin, NJ and the Chimney Rock Quarry in Bridgewater, NJ have produced the best coppers East of the Mississippi that I am aware of both large plates and crystalized specimens came from Chimney Rock Q.. A few of the Chimney Rock Q. pieces even had small silver crystals on them. Unfortunately I do not have pictures of the Large pieces.
Steve.

I have a 9" x 6" plate of native copper from Chimney Rock (Bound Brook, NJ) I can shoot to see if it makes the grade. No crystals, unfortunately. I do have an old, crudely crystallized copper from the Cornwall Mine in Lebanon Co., Pennsylvania that's on my list to photograph.

To date I've had a hard time making coppers look good with my limited photo set-up, else I would have more posted. I'll keep trying, though, as I have a lot of odd localities in the suite and am always hunting for more.

Actually, I should have looked before I posted. There are a number of nice coppers in the Chimney Rock page already, a couple of which show crystals or are really huge.

Chimney Rock coppers

I guess the question for any "Best Minerals" article is whether one goes exclusively for the premier specimens and localities or expands to the variety to include less attractive occurrences that are interesting or tell something about the mineral. One nice thing about Chimney Rock is that the locality description has a thorough discussion of the mineral occurrence -- nice job, whoever did that -- which could be distilled for the copper part and included in this article. As Rock pushes in the other "Best Minerals" threads, those chunks of commentary are what will add value to the overall project beyond providing eye candy.

For Michigan, some datolites with copper in them should be included: it is copper, the localities are known for it, and there is already a copper including calcite.

There are merit to all the things you talk about. Right now, David is the guy working on the Best Minerals-Copper article and I will let him decide what he will initially include in the article. All the Best Minerals articles are open for revision and additions with time. I would think that the best examples we have from Chimney Rock, Franklin and the Copper and Datolite should be ultimately included. Often, if someone will go to the trouble to writing up explanatory text to go beneath the pictures, that alone will be incentive enough for us to add the locality and images to the articles. Just some images of another ho hum copper may be reason enough to not include it, but if someone will write up some interesting and explanatory text about the copper from a particular locality is a powerful incentive for us to include it.

Rock Currier
Crystals not pistols.

With respect to copper inclusions. Most of the photos that we have don't really show it very well. The Centennial mine ones show a lot of alteration minerals rather than the native copper. We really could use a photo at higher magnification (a lot of the coloring in datolites is from hematite and not copper) We should also include the agates from the Wolverine mine, but I don't believe there are any photos uploaded yet.

How about this Copper specimen I have, [www.mindat.org] its certainly different/unique to others from this mine.

David,
Just a correction about Michigan copper/silver halfbreeds; while there are a number that have come from the stamp mills, the vast majority are naturally occurring in the deposit. I have never seen or heard of a halfbreed “created” by glacial action. I wonder if this came to be because of the copper/silver float coppers which are discovered occasionally. Also about the copper fans; that I know of, none of these were ever made for sale to tourists back in the day. They were created by the miners in advance to give as souvenirs to dignitaries and upper management when they visited the mines. There are not many around and even less available for sale.

I have a few datolites that show native copper inclusions, and you’re most welcome to use any of them that will suit your needs. Also, I have one of the copper included agates posted from Wolverine that again, you’re more than welcome to use. Below are a couple examples:

"Just a correction about Michigan copper/silver halfbreeds; while there are a number that have come from the stamp mills, the vast majority are naturally occurring in the deposit. I have never seen or heard of a halfbreed “created” by glacial action."

See page 183 "Mineralogy of Michigan"

David,
Thanks for the reply. I am very familiar with the Mineralogy of Michigan; see pg. 5 and you'll find my name there. And, as I read the paragraph you mentioned on pg. 183, I can't help but wonder if it is being misinterpreted a bit.

Quote
Mineralogy of Michigan, pg. 183
Some [silver] may have formed at the same time as the copper, thought most silver occurs in vugs and appears slightly later in the paragenetic sequence than copper (Butler and Burbank, 1929). Very few specimens show the converse relationship. According to Olson (1986), most of the nugget-like "halfbreed" specimens seen in the marketplace are products of the stamp mills, which crushed fine crystals and "amalgamated" the copper and silver. A very few of these intergrowths, however, may be natural, having been formed by glacial smashing and subsequently found in alluvial gravels.

It is important when reading this passage to note that the halfbreeds being referred to are only the nugget-like ones. It does not refer to specimens found underground, which obviously could not have been created or affected by glaciers or stamp mills. As I said earlier, I have never seen a halfbreed "created" by a glacier. All of the specimens I have seen are either the result of being put through a stamp mill (the nuggets), or, more than likely, they were formed naturally. The only halfbreeds I have seen affected by glaciers are the float specimens that sometimes show up on the market.