Green rock ...need help

[Gypsy Heart]

Help me on this ....in a river bed that was a glacier path, why would there be one large boulder that stands out....so out of place. It is about three by three feet,almost perfectly round,smooth and weighs (guessing here ) about four hundred pounds. It is the same color as a tarnished copper penny....hazy green. As an avid fly fisher, I have walked this river bed for the past fifteen years, ten miles of stretch and have found no other rock remotely similiar to it.
It is in Northern Wisconsin ,but at least 80 miles from Copper Falls or any of the mines...any clues
It is also right at the entrance of a small cave formed by gigantic boulders ( ten feet high and larger ) which I have crawled in numerous times. But this year am taking my MD with me inside...Usually dont carry it with because of the distance upstream and the fact that I have so many fish to carry back!!!!!!

 

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[kenb]

? ? Gypsyheart,
? ? ? ? ? ? ? ? I've got a 4" by 3" chunk of amethyst crystals that the back side of looks allot like what
? ?? ? ? ? ? ? you're describing, you may want to lug a sledge hammer upstream and whack it!!!

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? kenb

 

[Gypsy Heart]

Finally an answer...I plan on doing just that come spring.

 

[Gypsy Heart]

Ken b ...would it be possible for you to send me a pic of a amethyst rock before it was hammered on...or the backside of one...decided to take a winter hike and want to be a little more positive before I drag a sledge that far...cant drive to the spot so am hiking in through mountains of snow>>>>> Thanks

 

[Snee]

Whatever it is, my recommendation would be not to whack it with a sledge hammer. If it is a large geode, then it's worth a lot more professionally cut with a diamond rock saw than it is whacked into hundreds of little pieces. Below are some pictures of a few I have. The two side ones are amethyst and the middle one is citrine. I also compared the color of the one amethyst crust to a 1940 wheat I have that is pretty green. I hope this helps!

 

[Staroleum]

Those are great pictures of the geode and the penny!

Can you get a picture of the rock in question, Gypsyheart?
If it does seem feasible, you could bring a more easy to carry rock hammer back and try to chip of a small sample from an unobtrusive spot. Having a sample would make it easier to I.D.

Every once in a while I bring a box of rocks to the state geologist's office here in Portland. They are very nice and accomodating as long as I call them ahead of time and make an appointment. It's nice to live in the big city sometimes.

 

[kenb]

Gypsyheart,
sorry I missed you're post asking for a picture, the picture Snee posted with the penny
looks exactly like the one I have. Good luck smashing it, bring some goggles!!
kenb

 

[Gypsy Heart]

Thanks everyone...I have made plans to lug that rock out of there as soon as spring comes.....this out to prove pretty interesting

 

[bakergeol]

They are called glacial "erratics".

http://www.oceanlight.com/lightbox....=mountain_and_peak&x2=glacial_erratic_boulder


George

 

[bk]

Is there any chance that it may be native copper?

 

[Gypsy Heart]

Ok...I am about 60 miles from Copper Falls . The rock is in the river bed that goes through the National Forest.....I have fished and walked this river all my life and have walked miles up and down it both ways. I have also rafted it and then canoed it for twenty miles. There isnt a rock that I have seen that comes close to it in appearance.I thought that copper had a crusted appearance and this one doesnt....and I dont know enough about them....except I keep lugging them home ....but the color is a deep sage green that loooks like the photo that diamond jim was talking about......not far from there though people have found huge crystals in rocks....again they look like amithyst....but I just dont know......I will try to get some photos soon ....thanks everyone...

 

[Gypsy Heart]

Ok , I have a tow straps for cars...that Hook into a woven net that I fashioned using the same strapping incorporated with tie down ratchets ......the encompassing the rock in the net and with the tow straps pulling it up hill using two ATVS .........once up hill I can then drag it to the road.......where I have a friend (who owns a sand and gravel company) who will load it onto a flatbed and head her home!!! So I think I have the gtetting it out section covered ..........now if I can just determine what it is ....hahaha

 

[Jeffro]

An old VW hood makes a great sled for rocks, won't get nearly as beat up that way. Used to use one for my cobbles when dredging in low water streams. I'm no help identifying it without a pic at least, lol!

 

[Gigisdiamonds]

So what happened? Did you get ithome safely? Waiting to hear the rest of the story... Thanks HH Gigi

 

[Rockranger]

Smooth green and hard sounds like a gabbro rock

 

[nebraskadad]

Help me on this ....in a river bed that was a glacier path, why would there be one large boulder that stands out....so out of place. It is about three by three feet,almost perfectly round,smooth and weighs (guessing here ) about four hundred pounds. It is the same color as a tarnished copper penny....hazy green. As an avid fly fisher, I have walked this river bed for the past fifteen years, ten miles of stretch and have found no other rock remotely similiar to it.
It is in Northern Wisconsin ,but at least 80 miles from Copper Falls or any of the mines...any clues
It is also right at the entrance of a small cave formed by gigantic boulders ( ten feet high and larger ) which I have crawled in numerous times. But this year amtaking my MD with me inside...Usually dont carry it with because of the distance upstream and the fact that I have 8)so many fish to carry back!!!!!!

Gypsy,

It's likely glacial till from those mineral bearing areas from 10000-15000 years ago. It's amazing what glaciers can do.

 

[nebraskadad]

Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies. The belts have been interpreted as having formed at ancient oceanic spreading centers and island arc terranes. Archaean greenstones are found in eastern and northern Canada, western Australia, south and eastern Africa and Madagascar, west Africa and Brazil, and northern Scandinavia and the Kola Penninsula. Proterozoic greenstones occur in west Africa, northern Madagascar, northern Canada and northern Scandinavia.

The name comes from the green hue imparted by the chlorite minerals within the rocks. The belts often contain ore deposits of gold, silver, copper, zinc and lead.

One of the best known greenstone belts in the world is the South African Barberton Greenstone belt, where gold was first discovered in South Africa. The Barberton Greenstone belt was first uniquely identified by Prof Annhauser at the University of the Witwatersrand, Johannesburg, South Africa. His work in mapping and detailing the characteristics of the Barberton Greenstone belt has been used a primer for other greenstone belts around the world.

He noted the existence of pillow lavas, indicating a lava being rapidly cooled in water, as well as the spinifex textures created by crystals formed under rapidly cooling environments, namely water.

 

[thompy]

Hey Gypsyheart it is copper i would imagine, have you scraped it? the copper was pretty pure from up north, my folks have a piece of float copper about 1ft.x2ft.x 6" and probably weights 120 lbs,i don't think it would have been a problem for the glaciers to move it their. gold found in lower Mi. and Ohio in glacial moraines were originally from Canada and the U.P., I'm originally from Marquette, Mi and there is also greenstone in that area and old gold, silver and iron ore , further to the west the copper mines of the copper country. I read your post on the old Wi, copper mines, check out Michigan's Prehistory's Mysteries, it blew my hair back, dealing with the copper culture Indians, couldn't put the book down. Its kind of funny reading your post i figured you were located out west. HH Thompy