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Cleaning native copper

Posted by Kyle Eastman  
Re: Cleaning native copper
January 13, 2012 03:21PM
Rock Currier, Paul, Scott: Scott, what do I have to do to get my photos to come up like yours instead of "open-download" like mine turned out? Rock Currier, what is epidote and what does it look like? Paul, my wife and I bought a metal detector and spent three weeks in the upper pensinsula of Michigan going over old mine rubble???? - tailings???? in a learning process. We had a great time doing it and loved the beautiful scenery. I know Mandan mine, Phoenix mine, Central mine, Cliff mine, and anywhere else we saw piles of rocks while we were out driving the back roads. We even found lots of old bottles, some with the cork tops. We plan on going back up there again this year. We are not just interested in finding copper, we love exploring any and all rocks. Some of our friends and family laugh and say we have rocks in our heads, but we love it, we're retired, and its good exercise and good time together..
Re: Cleaning native copper
January 13, 2012 03:56PM

Ain't it great?! And the more you learn, the more enjoyable it gets. The crust of the earth is amazing...deep, in more ways than one. Having your wife share the interest is the best. I love my rock collection, but it can't love me back, can't even get coffee...
Type 'epidote' into mindat, you'll see plenty in the gallery. keep you occupied this winter.
Have you tried sandblasting a copper piece? I had an acid damaged galena that was expendable, it looked better sand blasted (w/o my glasses on). It is too soft, it looks pocky upon closer inspection but it took the crud off. Copper would fare better.

Take care,
avatar Re: Cleaning native copper
January 13, 2012 09:25PM
Can you be more specific about the photos you are talking about? Epidote is a green to black mineral often found associated with copper specimens from Michigan.

Rock Currier
Crystals not pistols.
avatar Re: Cleaning native copper
January 14, 2012 01:56AM
Sounds like you had a great time in "da UP" this summer, Bill. I also recognise all the mine names you mentioned as they are sites I am very familiar with. However, this thread is devoted to cleaning native copper, so I would suggest that if you want to continue talking about UP copper, geology, or its scenic beauty, maybe a Talk Page would be more appropriate.

Just a suggestion...
Re: Cleaning native copper
January 14, 2012 06:30PM
Mike - Rock Currier - Paul: Mike, I may try some sandblasting later on if I can come up with some extra bucks to get a unit. Mr. Rock: I was talking about I liked the way we all can see Scott's photos just by scrolling down. My photos had to be clicked on to open. Paul:..Sorry, I wasn't aware that there were limitations on what could and could not be discussed here. I need to get better accquainted with this website and what is available. I do apologize. Thank you very much to all of you that respond. I excitedly look forward to corresponding with you all. I will later on try to navigate to a "Talk Forum page" so I can ...BS..a little. I will however be back here too. Bill
avatar Re: Cleaning native copper
January 14, 2012 10:32PM
Sorry, haven't been by my computer much in the past few days.

Bill, you can add a photo in your post once you attach the file. There will be a button that title "Create Link in Message" once the file is attached to the message. What I usually do is type up what I want to add to a post, add the files, and then put my cursor down below my text a couple lines. I then click on the button to add the photo to the post (you won't actually see the photo until the post is made, but there will be a text line), drop down a couple lines, and do it again, repeating for all the photos.

Paul, I did not collect the Phoenix piece myself, so I am not entirely certain. I got it from the estate sale of a collector, and that is the information I was given at the time. I would much rather it be a Laker pocket piece of course, but really couldn't say, and I am not sure how that could be determined. Either way, I like the piece a lot, and even though it is small, it is one of my favorite coppers out of the many I have. There is just something about it that really appeals to me.
avatar Re: Cleaning native copper
January 15, 2012 12:49AM
If that is the information you were given Scott, then by all means go with it. If it came from an estate sale, more than likely it is from Phoenix as the Laker Pocket material is quite new on the market.

It's not my decision Bill what can be discussed on here, that's for the managers. It was more of a suggestion that if you wanted to chat about other things besides how to clean copper to start a locality talk page on the Copper Country, and there you could really have a grand discussion about all things Keweenaw. grinning smiley

Earlier you were asking about epidote; here is an example from the Centennial No. 2 Shaft in Houghton Co.
Re: Cleaning native copper
January 15, 2012 04:18AM
I think that thet the dull gray to black patina on native copper and native silver might actually be copper and silver sulfides.

Copper and silver are sulfur getters. They draw sulfur out of the air.

I wonder is a quick flash in diulte nitric acid might produce a tolerable and not overly bright finish.

I've used "Linde A" polishing compound applied and rubbed with a stiff artist brush to produce a "natural" looking clean-up on both native copper and native silver.
avatar Re: Cleaning native copper
January 15, 2012 05:37AM
Some of the cleaning methods got me thinking about a reverse process. Since I dont like really shiny clean pieces, I was wondering if there was a method to speed up the tarnishing or oxidation process on a piece that has been recently cleaned. Perhaps some way to make it look old a bit quicker.
Re: Cleaning native copper
January 15, 2012 07:54AM
I've noticed that some copper when being rinsed in water to wash off any remaining acid will oxidize if left in the water for a day or more. It appears that whether or not the oxidation is fast, slow, or non existent depends on the chemical makeup of the copper. I've had specimens that had to be taken out of the rinse and either blown or sun dried immediately or they would oxidize. Others could soak for days and still come out bright! Same in the cabinet, some of the copper is fairly oxidized after only in a few months and other pieces have been in the cabinet for years and are still shiny. Also had both results from the same mine. I use sulfamic acid exclusively for any acid cleaning. Natural and just washed and scrubbed or pressure wash is my preferred cleaning method. Unfortunately it seems that the majority of the specimens I collect have some kind of nasty coating that usually has some calcite next to the copper. Acid works fine. My experience has been that HCL no matter how dilute and how short a duration the soak it etches copper crystals and rounds off all the sharp edges of the crystals. Sulfamic undoubtedly etches the copper, but at a rate so slow I can not discern any damage. Sulfamic acids main use is for cleaning out boilers. Usually comes as a white powder in 50lb. bags.
Good Luck,
Re: Cleaning native copper
January 15, 2012 03:05PM
I have a big pressure washer I use for cleaning the skidloader, tractor, etc. Is this what you fellows are talking about using on cleaning copper, or is it some small unit for crafts and hobbies? Thank you. Bill
avatar Re: Cleaning native copper
January 15, 2012 07:02PM
Bill, it is a little handheld unit that directs a thin stream of high pressure water to the piece. It has worked wonders for me in cleaning so many specimens of so many minerals that I don't know what I would have done without it. You do have to be careful with certain minerals low on the hardness scale, but you can adjust the spray quite a bit. I believe the units were originally developed for the garment industry, but that have proved quite beneficial to mineral collectors everywhere.

I can't sing the virtues of this cleaning enough. I have more than a handful of specimens that elicited "Oh my gosh!" moments after I gave them a go with the water gun, including one especially funky Siderite with Pyrite from Eagle Mine. It is really great for copper because you don't have to worry much about being too careful, unless there are accessory minerals. Quite a few people and dealers sell them, and you should be able to find them fairly easily. I bought mine for about $80 a few years ago, and it has performed flawlessly since.
Re: Cleaning native copper
January 16, 2012 02:27AM
Scott: Thank you for answering my question about the pressure washer. I'll see if I can come up with one. Bill
Re: Cleaning native copper
January 16, 2012 02:54AM
Scott's idea is probably better than sand blasting, but ran into a guy who was strapped financially, but had some ingenuity; He took stuff he found, larger pieces anyway, down to the carwash, secured them some way, then used that power wand on 'em! i got a kick out of that. A country boy can survive I guess...

Re: Cleaning native copper
January 16, 2012 06:22PM
I could do that with the big pressure washer I've got except that right now the ground is covered with snow and ice. I think I'll try to find one of those small pressure washers. Bill
avatar Re: Cleaning native copper
January 16, 2012 06:42PM
Okay, the weather was a bit nicer, so I went out to the camper and grabbed the other pieces I had referred to that I kept stored out there. I am going to create a handful of replies to get the information up and post the photos. The first few sets are of the larger piece I had previously mentioned. This is the one that is primarily copper, with a wrapping of matrix material. Looking at it, the piece almost seems like the remnants of an infilled vesicle, with part of the "rind" of the vesicle attached.

On this piece, I can see some decent copper crystallization peeking out, as well as a few decent crystals already exposed. The first shot is of the whole piece, what I would consider the front, and the second is a closeup. Subsequent posts will show other angles and more of the matrix. As you can see on these shots, there is some calcite attached. While the periphery calcite is damaged, there are some very nice smaller crystals in the center, and I would rather not damage these. I am not sure if it can be seen, but there are a few areas with a coating of micro-crystalline quartz as well. This entire piece is about 10cm x 10cm.

open | download - Copper Specimens_010.JPG (104.8 KB)
open | download - Copper Specimens_011.JPG (169.4 KB)
avatar Re: Cleaning native copper
January 16, 2012 06:49PM
The pictures came out a bit overexposed, because I had some extra lighting on it to try to illuminate all the nooks and crannies. Offhand, I can't recall where this piece was found, but I have it written down on a master list in the larger box I had the pieces in, just forgot to grab that.

This second set of photos shows how the matrix material wraps around the copper. It is almost like the copper was encased in it (and it most likely was if my assumption is correct). At points where they meet, there is actually a small gap which I think I may be able to exploit to separate them. There is some layering extending outward, including a thin layer of pistachio green epidote where the matrix meets the copper. This matrix is very porous and somewhat crumbly, and peppered with very tiny crystals of various accessory minerals, especially in the larger bubble remnants. Based on the porosity of it, I thought it would break off a bit easier than it has. Still, with several goes from the water gun, I have been able to whittle away at it.

open | download - Copper Specimens_012.JPG (113.8 KB)
open | download - Copper Specimens_013.JPG (145.4 KB)
open | download - Copper Specimens_014.JPG (141.3 KB)
avatar Re: Cleaning native copper
January 16, 2012 06:52PM
This third set, from the same piece, shows various angles. The first photo shows a bit of a closeup of the porous matrix, on what I would consider the back/bottom of the piece. The second photo shows the layering and the epidote at the join. With the third photo, I tried to capture a small pocket on the lower right center of the piece. This didn't come out as good as I'd hoped, but it is still visible. There is some interesting crystallization in this pocket.

open | download - Copper Specimens_015.JPG (195.5 KB)
open | download - Copper Specimens_016.JPG (166 KB)
open | download - Copper Specimens_017.JPG (137.5 KB)
avatar Re: Cleaning native copper
January 16, 2012 06:58PM
These shots are from another piece, I believe from the same location as the piece I just posted. This one is a bit smaller, and definitely does not have as much potential, but it is a bit interesting to me. It is about 10cm x 5cm and again, I can see some crystallization poking out. However, on this piece, the matrix seems to be layered in with the copper, and has been very difficult to remove. Not to mention, the rock material is much harder, and it is difficult to tell when the rock ends and the copper begins. I doubt the matrix material would be affected by a chemical dip. I have been going at this one with the water gun as well, but the results haven't been much different than the original piece. I do like the coloration the accessory minerals have provided. On the last photo, you can see where the water gun has torn apart a calcite pocket. It was heavily damaged already, so I did not regard it as something to work around.

open | download - Copper Specimens_018.JPG (101.5 KB)
open | download - Copper Specimens_019.JPG (129.7 KB)
open | download - Copper Specimens_020.JPG (94.1 KB)
avatar Re: Cleaning native copper
January 16, 2012 07:03PM
This next series of photos details the Phoenix piece I tried to chemically clean. It is a branching piece that was almost completely covered with a thin layer of calcite. It spent a few minutes in a bath of dilute HCl and came out looking like this. It was my first experience using copper with HCl and I was extremely disappointed, to say the least. As you can see, it looks fried, and any decent crystallization is gone.

open | download - Copper Specimens_021.JPG (77.1 KB)
open | download - Copper Specimens_022.JPG (74.4 KB)
open | download - Copper Specimens_023.JPG (97.2 KB)


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