FMF - Friends of Minerals Forum, discussion and message board

[PeterOTool]

Hello,

I found this in the woods while picking mushrooms.

I am not sure if it is stone or what.

It does not react with magnet.

It is dark color with green points.

[Peter Megaw]

Where were you picking?

[Bob Carnein]

I'll bet you're picking mushrooms in Michigan (not the Moon). Looks like native copper. I would scrape it lightly with a knife in an inconspicuous place. If it's copper, it will be obvious to you immediately.

[PeterOTool]

Thank you very much Bob. I did that knife test and it is definitelly a copper !

Does it have some value or not ?

[James Catmur]

This site is non-commercial and does not talk about values. Having said that moon copper would be very interesting, but earth copper less so.

[PeterOTool]

Are there any methods to clean it gently to make it look more like copper and not destroy this nugget ?

[James Catmur]

If you clean it you destroy it, from our point of view. It looks like most of it has altered, so it's hard to say how to clean it

[Susan Robinson]

Have you cleaned it at all yet? I would say start with soap and water and a plastic scrub brush. I would not use a copper cleaner on it, since that will remove the naturally weathered patina.
You said you were searching for mushrooms in Michigan - were you in the Lower or Upper Peninsula of the state? The copper you have is typically called "float copper", since it was likely transported by the glaciers during the Pleistocene. Its origin would probably be the Keweenaw peninsula.

[PeterOTool]

Thank you for your messages.

I will not clean it at all, because I do not want to destroy it.

I only put it in distilled water, to remove the clay naturally. Or maximum I will gently
remove the clay with the soap or distilled water and child toothbrush.

I will probably give it to some museum, if they would be interested.

Unfortunately I am not from the US.

I am sorry for the confusion.

I live in former Czechoslovakia - now Czech Republic in Europe, near Prague, where I found it in the woods this weekend during a mushroom hunting trip.

[James Catmur]

The confusion came from your 'moon' posting - the location where you found it does help us identify minerals, so if you had given the location it that might have changed our opinion (probably not in this case)